text:
Talk:Calculus/Limits/An Introduction to Limits

Requests
While it's asked how | lim [x -> 0]{sin(x)/x} = 1 | can be proven, this isn't demonstrated - there also isn't an actual demonstration elsewhere online, nearly as I can determine. Shouldn't one be put in? --68.212.77.222 23:05, 26 Apr 2005 (UTC)

Is there anyone interested in writing How to evaluate the limit of a real-valued funtion ? --wshun

I think we should put the formal definition of the limit right at the end of page. As it is the most difficult concept to full grasp. And we need some excercises.

The last example seems to imply that f(x) = (x^2 - 9)/(x - 3) is not the same as g(x) = x + 3. Why is this true?

Because you can't divide by zero; g(3) = 3 + 3 = 6, whereas f(3) = (3^2-9)/(3-3) = (0/0) = undefined. The functions will, however, be equal at all other points. (yes I edited your question to make my answer easier to articulate. :) )

BTW, I would consider completely deleting the introduction. It makes some questionable statements, and I can't see it as being anything but confusion for someone who doesn't know anything about limits already. --Xhad

Am I the only one that thinks that this whole thing is worthless without the Cauchy definition of a limit? You cannot proove any of the statements unless you define limits properly. The best way to define them is the Cauchy definition!!

arbitrary break
(x^2-9)/(x-3) has the problem of a loss of information as x approaches 3. The solution to this is rearranging the problem so that you are no longer dealing with having a small number on the denominator. This is the realm of computational mathematics, though, and I'm not sure if it's useful to put in a Calculus textbook. --Ronald Raygun

To me that sounds like something that would be appropriate for a Calc primer for physicists, but it seems beyond the scope of a typical Calculus course. --Xhad

It would be neat if someone would implement a parser that would feed this latex math notation to a graphing program... easy visualisation on the click of a function. -- Kowey 09:03, 4 Oct 2004 (UTC)

Can any-one tell me that if we are taking x->0 and f(x)->L//then why are puting there an = in the answer when it should be ~(approximate value) --221.135.232.166 10:19, 27 June 2007

To answer the above question, it is because of the definition of a limit. Although we think of $$ \lim_{x \to c} f(x)$$ intuitively by the process of taking values of $$x$$ closer and closer to $$a$$, the limit is not formally related to the value of $$f(x)$$ at $$x=a$$, which may not even be defined. For instance, consider the function defined as follows:

$$ f(x) =\left\{\begin{matrix} 0 & \mbox{if } x\neq 1 \\ \mbox{27} & \mbox{if } x=1\end{matrix}\right. $$

By the definition of limit, $$ \lim_{x \to 1} f(x)=0$$, which is a really bad approximation of $$f(x)$$ at $$x=1$$. Greenbreen (discuss • contribs) 13:15, 16 March 2011 (UTC)

Possible inclusions for this page
- limits at infinity (horizontal asymptotes) - Infinite limits (e.g. vertical asymptotes) - Left/right handed limits - thinking of limits of indeterminant forms  (those that can be evaluated without Lhopitals rule)  - proofs of limit rules/one side limit theorem

Maybe this page needs to be broken up. Continuity is a whole topic, and the formal definition/proofs of limit rules could also be pulled to its own page. -- julius

dutch
Hey there, I'm making a dutch version of this book/chapter. I think I may have solved some presentational problems so if you like check out http://nl.wikibooks.org/wiki/Analyse:Limieten. Robert Zboray

LEDE
The section named Finding Limits starts as follows: ''Now we will concentrate on finding limits, rather than proving them. In the proofs above, we started off with the value of the limit. How did we find it to even begin our proofs?'' I find this confusing. There are no proofs above that I can see, only examples. And in those examples we did actually find the value of the limit. (I realize that this error is probably a rest from a previous re-dispositional edit..) Or am I missing something? In that case I apologize. /Hugo --83.181.53.162 20:31, 5 November 2006 (UTC)

You CAN divide by zero
EVERYONE LISTEN TO THIS. I'M TIRED THAT EVERYONE KEEPS TELLING THAT YOU CAN'T DIVIDE BY ZERO. Of course you can; it's a limit.

lim x/y = a. When y approaches zero, a = infinity.

 * Technically, you can divide by y in the limit as y approaches zero. You cannot divide by zero without the use of such a limit. Remember that:
 * $$\lim_{y \to 0} y \ne 0$$
 * The limit never allows y to actually take the value of zero, only to approach that value by infinitessimal amounts. As such, y never equals zero, but instead equals a value infinitessimally close to zero. The two quantities, while close, are not strictly the same. --Whiteknight (talk) (projects) 20:33, 9 January 2007 (UTC)

Whoa! I'm going to have to set this straight. You can't divide by zero, neither algebraically nor analytically. In algebra, the defining quality of the additive identity, zero, is that it has no multiplicative inverse (unless the set is trivially {0}).

PROOF:
 * Assume that zero has an multiplicative inverse, and let 0 * a = 1.
 * b*a + 1 = b*a + 0*a = (b + 0)*a = b*a  (assumption, distributive prop., def. of additive identity)
 * which means that 1 = 0, which is a contradiction whenever the set is not {0}.

Let's look at it analytically now. Remember, a limit has to be well-defined to exist. If it takes on different values depending on the way you approach the limit, then the limit doesn't exist. Back to your example:
 * lim(y->0) x/y. Without loss of generality, let x > 0 (if x = 0, then the limit is 0, and if x < 0, we can multiply it by -1)
 * lim(y->0 from the left-negative side) x/y < 0 and lim(y->0 from the right-positive side) x/y > 0
 * Therefore the limit is not well-defined. It doesn't exist.

Now, you could try to patch it by definition, but no matter what you'll be left with some "infinity" which isn't accounted for. Also, negative infinity is not equal to positive infinity... that's easy enough to see.

Lastly, to the point: $$\lim_{y \to 0} y = 0$$. If one uses the formal definition this is obvious. There is no actual "approaching" - that's just a simple way to think about it. "The two quantities, while close, are not strictly the same" - They are only different in that they have different names. (Sketch: Let the infinitesimal x (>0) be a number different from 0, so that x/2 is not 0. Then |y - 0| < x/2. Obviously y cannot be x, for x <= |x| = |x - 0| < x/2 is a contradiction.) The infinitesimal is a nice tool for investigating functions of limits, but technically it's not a number in the sense you're trying to use it. Mo Anabre 06:43, 1 May 2007 (UTC)

 * I did simplify too much in my explanation, i should have taken the time to explain it properly. --Whiteknight (talk) 17:37, 1 May 2007 (UTC)

Hello! Intuitively, zero is a special symbol (like $$\infty$$), that denotes empty expression. But if there is abscence of anything, what are you trying to compare with divident? Of course, division by zero can be defined artificialy, but AFAIK all such definitions lead to contradictions with other axioms. Exanode 15:16, 7 November 2007 (UTC)

There are two limit of each function (though sometimes both give the same result), one from the positive side and one from the negative side, so actually you can take the limit of x/y as y approaches 0. This is also a mistake in the text, which says that the limit of 1/(x-2) as x approaches 2 is undefined. The limit of this function from the negative side is negative infinity and the limit from the positive side is positive infinity.

TO: authors.
Please put some visualizations in the text. It's best to describe things like limits with graphics and give viewers an intuitive visual analogy.

I've seen some very interesting eLearning math courses with lots of graphical analogies. It made the concept of functions limit (among other things) easily understandable. Unfortunately the said courses are copyrighted and closed source.

 * That's a great suggestion! If you have images or visualizations that you would like to donate, or if you know where we can find free or open-source images that we can use, that would be great. Unfortunately, creating lots of images takes time, and we are all just volunteers here. If you would like to join our project and help out, it would be appreciated. --Whiteknight (talk) (projects) 21:24, 10 January 2007 (UTC)

 * Do you mean adding images to (for example) the Sqrtx216.gif function? There's a link to an image link there - I can't decide whether it is a old link that's been deleted or a request for a new link. DavidMcKenzie 15:40, 6 February 2007 (UTC)

Shouldn't we start with the values approaching a particular value? That makes it a lot easier to understand.

Conversation
For what it matters, after learning a little more about formal continuity, density isn't even required. For instance, every function on the integers is continuous (since as a subspace of R, they have the discrete topology). Also, something interesting for anyone reading the person down there below Eric119: the integers are complete. Mo Anabre 20:59, 1 November 2007 (UTC)

I changed it back. The density of the rationals in the reals is quite enough to justify a concept of continuity of f. Mo Anabre 17:48, 1 May 2007 (UTC)

I don't understand why this is wrong. If the domain of f is only the rationals, then, according to our definition of limits (which seems to have vanished from the article), no matter what delta we have there will exist irrational x such that 0 < |x - c| < delta and thus f(x) is not defined and therefore the condition |f(x) - L| < epsilon cannot be true. (And then there is no limit and therefore a discontinuity.) If there is a problem in all this, please let me know. Eric119 01:28, 6 Sep 2004 (UTC)

this is just wrong! The real number line is complete, meaning there are no holes. However, if we say f (x) = 2 and restrict the domain of f to rational numbers, there will be holes at the places corresponding to irrational numbers. There are irrational numbers between any two rational numbers, so all the rational numbers on which f is defined are isolated from each other. But, there are rational numbers between any two irrational numbers, so each hole must be at a single point. There are infinite irrational numbers over any interval, so there are an infinite number of infinitely small holes between any two points on the graph. The places where f is defined are also infinite and infinitely small. The function f has no limits defined anywhere, despite that any graph would look like a simple line.

application to calculus out of context
The "application to calculus" section references an example and several figures that don't exist. I presume that the section was copied over from some other source, and either the context and figures were neglected, or they were deemed a copyright violation and deleted (but the "application to calculus" section remained). Please rewrite this section so that it no longer references material that doesn't exist on wikibooks! Thanks! Luvcraft 17:26, 2 July 2007 (UTC)

application to calculus out of context another note
I think - that limit itself has no too much "independent" uses... Actually - it is instrument for establishment of strict differentiation theory... So - I would just abandon this item... Good illustration of use of limit concept could be concept of tangent line, or "moment velocity" vector... But - they are once more - from field of physics and geometry, and not - pure calculus... --Simonovsky Pavel 18:29, 10 October 2007 (UTC)

As x ->0 sin (1/x) ->0
Sin (1/x) has no limit as x approaches 0. I have sources. The chapter must be changed. Zginder 13:43, 12 September 2007 (UTC)

Zginder, did you even read the section? I'm putting it back and fixing the _one_ error you didn't like. In the future please try to fix typos before deleting whole sections because of them. Mo Anabre 20:53, 1 November 2007 (UTC)

Problem with 'Limit rules'
Why are all the limit rules listed with no proofs? Shouldn't the be proven before they are given? 142.151.186.71 04:38, 9 October 2007 (UTC)
 * Agreed. Maybe the proofs can be put in an appendix with a working link from the 'Limit Rules' section or at the very end of the module. --Hamsterpoop 05:21, 29 October 2007 (UTC)
 * If it get some time here I'll try to come up with some of them, shouldn't bee too hard. 142.151.186.71 20:41, 3 November 2007 (UTC)

Began Edit
I started editing the beginning of the page, trying to start the discussion of a limit in a way that I (modestly) felt was more engaging, and tried to integrate it with the rest of the text. I hope to come back and try to do more work.

Thanks.

128.208.76.146 (talk)

Formal Definition of a Limit
Was the formal definition of a limit completely removed, or moved somewhere else? If the former, why? RSiferd (talk) 05:11, 21 May 2008 (UTC)
 * It appears later in this "chapter" Calculus/Formal Definition of the Limit. And again, almost identically, at Calculus/Formal limits. --Mrwojo (talk) 19:22, 28 December 2008 (UTC)
 * I've merged them at Calculus/Formal Definition of the Limit. --Mrwojo (talk) 05:54, 13 January 2009 (UTC)

Video?
Does wikibooks have embedvideo extension installed?

It does not appear to. Should it? Or some other video extension? Can we request this?

Introduction to Limits Lecture

~serundeputy

Infinite oscillation is redundant
The section on infinite oscillation is very redundant. Maybe it could be shortened? 173.74.178.117 (talk) 01:29, 7 July 2010 (UTC)

 * Thanks for the comment. There are not many people working on the book right now, so it could be a few years before someone acts on this comment.  But you can feel free to be bold and remove any parts that you don't like.  Don't worry, people quickly look over things that change because of the whole "watchlist" setup, so even if your just learning calculus yourself or an old pro you can still be an equally valid contributor.  You can do so with or without an account, but I usually recommend having one, so you can configure your preferences. Thenub314 (talk) 16:00, 7 July 2010 (UTC)

About mentioning L'Hôspital's rule with example 6
L'Hôspital's rule was briefly mentioned for finding the $$\lim_{x\to0}\frac{\sin(x)}{x}$$. However, this is technically mathematically incorrect because it would require you to know $$\frac{d}{dx}\left[\sin(x)\right]$$. This limit is something one would find when trying to prove the derivative of $$\sin(x)$$, so this means using L'Hôspital's rule is incorrect for this particular limit. I was wondering if I should delete the mentioning of L'Hôspital's rule and make a dedicated page proving "the limit." I am asking here to be sure no one minds this. Musical Inquisit (discuss • contribs) 03:45, 13 July 2020 (UTC)


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User talk:RoseParks~enwikibooks

Hi! It seems we meet again, after the Nupedia experience (though I remember seeing you on wikipedia occasionally?). Thanks for the fixes in thermodynamics. Most of these were typos and not my bad English, rest assured :-)

Do not fear to run out of work, I plan to write lots more on the biochemistry front! --Magnus Manske

Good to be in contact, again. You are either in a big hurry or your English is slipping...and I am sure I know which ;-) --RoseParks

Your account will be renamed
Hello,

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Unfortunately, your account clashes with another account also called RoseParks. To make sure that both of you can use all Wikimedia projects in future, we have reserved the name RoseParks~enwikibooks that only you will have. If you like it, you don't have to do anything. If you do not like it, you can pick out a different name.

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Renamed
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license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/

title: User talk:RoseParks~enwikibooks


text:
Wikibooks talk:Neutral point of view

I think the NOV policy needs some discussion for wikibooks project.

We may agree that wikibooks should not a place to produce a book that asserts some specific position or view, though I am not completely sure.

Should we say, for example, there should not be a book about environmental conservation (or gun control or birth control) that asserts that conservation is important? (The more NPOV way of referring to that is "many (including, A, B) think that conservation is important because of ..., though there are some criticisms, most notably by C that ...."

In case of encyclopedia, there is a solution - we can sometimes split an article into many articles, and explain different points of views in length.

If we were to implement this kind of solution, we might want to develop multiple "modules" or components of books along with multiple table of contents (each of which take different sets of modules to create a book from one particular POV).

Feel free to copy this to mailing list or elsewhere. Tomos 22:54, 31 Aug 2003 (UTC)
 * I agree that NPOV will have to apply differently here than Wikipedia. Since the project is still nascent, the best bet is to just go with it and, hopefully, a consensus will develop over time -- since most of our regulars are likely also Wikipedians, I think this will be a relatively easy process.  The conservation textbook you mentioned is a good example; it would be silly to interrupt every point with an explanation of why not everyone believes it.  The same would apply to descriptions of evolution, the Big Bang, etc.  We can assume a particular POV on the part of the reader in these cases, and should probably include an introduction or preface that explains why we are ignoring the fact that not everyone believes the same way on these issues. TUF-KAT 18:00, 12 Oct 2004 (UTC)

My opinion is that NPOV is not really at home here. Textbooks and other learning materials at times are written, and NEED to be written, from a "non-neutral" point of view. --Karl Wick 21:51, 12 Oct 2004 (UTC)

 * I'm pretty new here, but I strongly belive that NPOV is not appropriate for Wikibooks. I think that there is, perhaps, some questionable sort of "objectivity" that something like an Encyclopedia can strive for, but I do not think this the case with a book. Limiting ourselves to books that meet an-NPOV standard would limit ourselves to books that sound an aweful lot like encyclopedias. Wikibooks seems to be about something beyond that.

 * Furthermore, since Wikibooks is trying to create textbooks or books that could be used for learning, in a project like Wikiversity, etc., I think it is important to recognize that "objective" truth is a POV that tends to privilege the status-quo. Like the above example, if you are writing a book on environmental conservation, I believe it would not only be "silly" to strive for NPOV, I believe it would be counter-productive. As a history student, I believe that every narrative has an implicit subjectivity, (or POV). Any narrative that is constructed, for instance history, anthropology, sociology, etc., comes from a point of view and has political implications. The notion of "objectivity" and "objective truth" for instance in Anthroplogy, has been used to blind people from the significance of privileged white male anthropologists observing other cultures. (And Anthropology, with its claim to "objective truth," has played a vital role in the construction of scientific racism.)

 * I'm sorry if I'm trailing off here... I just feel strongly that recognizing subjectivity as opposed to hiding from it is a more fruitful approach to something such as Wikibooks. Fokion 23:36, 11 September 2006 (UTC)

If there is a need to have something written from an non-NPOV, then that need should (will?) be clearly noted in the text itself. The real question of NPOV is what does 'neutral' really mean? That should be clearly defined in the policy. My initial idea is that if something exists to be talked about factually, there is something in empirical reality that can be cited, and ought to be cited. Conclusions and opinions based on that empirical concepts should be built logically. If there are any countering opinions (or significant counter theories) they should be explained as if they were subject to the same rules. --Neal Delfeld 18:24, 11 November 2005 (UTC)

 * I think a problem here is that the idea of talking "factually" and "empirical reality" may work well with something like computer science or mathematics, but not so well with history or social theory. History, for instance, is not made of concrete facts, one stacking upon another. NPOV may work better with the "hard" sciences, but in the humanities or social sciences there is no such thing.Fokion 00:16, 12 September 2006 (UTC)

POV in textbooks
I think our history, geography and Chinese history textbooks are almost certainly biased. Especially history. You know, the 'the ancient Egyptians were great architects' or 'Alexander the Great was a great ruler'. For the ancient Egyptians they even gave the wrong fact because they followed Herodotus' version. But to the smaller ones. Like 'the Spartans are a warlike people'. Most people agree that, don't we? By modern standards they are pretty warlike. But is that still an opinion, an opinion to the eyes of us modern people? And one more thing: Athenians built many open-air theatres. What defines many? There could be theatres on every corner of Planet Drama. :)

By the way, I think the emoticon should be removed. It makes our policy here look much more casual. Policies and guidelines can joke, sure, WP does that all the time, but not include non-standard ways of expressing. Kayau ( talk | email | contribs ) 23:56, 18 June 2010 (UTC)

 * They say that history is written by the victorious. Of particular note to your thoughts is Can history be truly NPOV?. – Adrignola talk 03:22, 10 October 2010 (UTC)

 * Ha. I have to agree. Chinese history, for example, is written from a Confucian point of view. Kayau (talk | email | contribs) 03:32, 10 October 2010 (UTC)
 * Compared with Wikipedia our NPOV policy is much more casual. I think Wikipedia expects their articles to be written neutral from the beginning while Wikibooks accepts that neutrality is a process that takes time. Wikipedia's expectations are reflected in that its policy defines what it means for articles to be neutral and how to achieve neutrality while Wikibooks relies on the scope of each book to affect what it means to be neutral and how neutrality is achieved which is reflected by the more general and less specific approach used in Wikibooks' policy.
 * If you believe the statements above that you quoted are a problem, be bold and fix them. "Anthropologists like Blah and Blah considered the ancient Egyptians to be great architects" or "During his time people considered Alexander the Great to be a great ruler, hence the name" to give two possible fixes. For the smaller ones you could even do "Compared with modern standards the Spartans are a warlike people" or "Today the Spartans are considered warlike people." --dark lama  13:08, 10 October 2010 (UTC)

title: Wikibooks talk:Neutral point of view


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Cookbook:History of Food and Cooking

The origins of cooking began with primitive humans roughly 2 million years ago. There are various theories as to how early humans used fire to cook meat. According to anthropologist Richard Wrangham, author of Catching Fire: How Cooking Made Us Human, primitive humans simply tossed a raw hunk of meat into the flames and watched it sizzle. Another theory claims humans may first have savoured roasted meat by chance when the flesh of a beast killed in a forest fire was found to be more appetizing and easier to chew and digest than the conventional raw meat.

Culinary techniques improved with the introduction of earthenware and stoneware, the domestication of livestock, and advancements in agriculture. In early civilizations, the primary employers of professional chefs were kings, aristocrats, or priests. The divide between professional chefs cooking for the wealthy and peasants cooking for their families engendered the development of many cuisines.

A great deal of the study of culinary arts in Europe was organized by Jean Anthelme Brillat-Savarin, a man famous for his quote "Tell me what you eat, and I will tell you what you are," which has since been mistranslated and oversimplified into "You are what you eat." Other people helped to parse out the different parts of food science and gastronomy. Over time, increasingly deeper and more detailed studies into foods and the Culinary Arts has led to a greater wealth of knowledge.

In Asia, a similar path led to a separate study of the Culinary Arts, which later essentially merged with the Western counterpart. In the modern international marketplace, there is no longer a distinct divide between Western and Eastern foods. Culinary Arts students today, generally speaking, are introduced to the different cuisines of many different cultures from around the world.

The Culinary Arts, in the Western world, as a craft and later as a field of study, began to evolve at the end of the Renaissance period. Prior to this, chefs worked in castles, cooking for kings and queens, as well as their families, guests, and other workers of the castle. As Monarchical rule became phased out as a modality, the chefs took their craft to inns and hotels. From here, the craft evolved into a field of study.

Before cooking institutions, professional cooks were mentors for individual students who apprenticed under them. In 1879, the first cooking school was founded in the United States: the Boston Cooking School. This school standardized cooking practices and recipes, and laid the groundwork for the culinary arts schools that would follow.

Historic texts
The origin of many modern dishes can be traced back to ancient times, but there are very few surviving texts written before 1000 AD that deal with cooking. In many cases where texts exist, the recipes and directions they provide are little more than guidelines and assume much knowledge on the part of the cook.

For example, the following is a recipe taken from the Forme of Cury, a roll of cookery written around 1390 by the master cooks of King Richard II of England. It is written in late Middle English, is open to interpretation as it gives no specific quantities, and assumes that the reader will know how long certain things need to be cooked, soaked, etc.: Compost

Take rote of persel, of pasternak, of rafens, scrape hem and waische hem clene. Take rapes & caboches, ypared and icorue. Take an erthen panne with clene water & set it on the fire; cast alle þise þerinne. Whan þey buth boiled cast þerto peeres, & parboile hem wel. Take alle þise thynges vp & lat it kele on a faire cloth. Do þerto salt; whan it is colde, do hit in a vessel; take vyneger & powdour & safroun & do þerto, & lat alle þise thynges lye þerin al nyyt, oþer al day. Take wyne greke & hony, clarified togider; take lumbarde mustard & raisons coraunce, al hoole, & grynde powdour of canel, powdour douce & aneys hole, & fenell seed. Take alle þise thynges & cast togyder in a pot of erthe, & take þerof whan þou wilt & serue forth. You shouldn't let this deter you from reading old texts concerning cookery; indeed there is a certain degree of fun in taking an old recipe and determining how it might have been prepared.

title: Cookbook:History of Food and Cooking


text:
Talk:Computer Programming/Variables

The introduction to variables may make sense for a course to "Programming C" and a like. But in a more broader context it does not satisfy me. Some thoughts:

Variables may reference values rather than stand in for. You can make the variables to reference to another value later on in the program, you can have to variables to reference the same value and you can then manipulate these value through either variable.

The later is explained in the text, but we may abstract from "memory addresses" here.

Moreover, there are programming languages where you have to declare a variable before you can use but don't need to give it a type. I'm thinking of Oz here. In some dynamically typed languages like ruby, procedures/functions/methods declare proc./func./method need arguments (which are variables) declared but without a type.

 * Your points make sense...why don't you edit the page?
 * This 'book's in a bit of a larval state still and still needs some work Dysprosia 09:16, 1 Sep 2003 (UTC)

 * textbook.wikipedia.org was just mentioned in a couple of slashdot comments (not articles! don't panic!). I doubt that there'll be lots of people arriving but there might be a few gawkers moving through.

 * I tried to edit the introduction but could not figure how to get to it.
 * What I was trying to add
 * Dates and times can be in various formats such as USA (mm/dd/yyyy); European (dd.mm.yyyy); Japanese (yyyy.mm.dd); based on Chinese Year (not Biblical); and others.

AlMac 09:25, 16 July 2005 (UTC)

title: Talk:Computer Programming/Variables


text:
Cell Biology/Lysosomes

Cell Biology | Parts of the cell | Organelles

<< Golgi apparatus | Lysosomes | Peroxisomes >>

Lysosomes
Membrane-bound sacs called lysosomes contain digestive enzymes that can break down such macromolecules as proteins, nucleic acids, and polysaccharides (Figure 6-23). Lysosomes have several functions. They fuse with incoming food vacuoles and expose the nutrients to enzymes that digest them, thereby nourishing the cell. Lysosomes also function like safety officers when they help destroy harmful bacteria. In certain cells—for example, your white blood cells—lysosomes release enzymes into vacuoles that contain trapped bacteria and break down the bacterial cell walls. Similarly, lysosomes serve as recycling centers for damaged organelles. Without harming the cell, a lysosome can engulf and digest another organelle. This makes molecules available for the construction of new organelles.The structures vary in size from 0.2 to 2 micrometers in diameter. The staining reveals a crystal like matrix in spherical vesicles. The crystalloid matrix is urate oxidase. These are small organelles containing around 40 enzymes for intercellular digestion. The lysosome membrane helps to protect the enzymes as much as it helps protect the cell. This is because the optimal pH for these enzymes is around a pH of 5. The membrane of the lysosome is again a lipid bilayer and is thought to have a ATP hydrolysis to pump H+ into the lysosome to maintain the pH. This also has another affect, that is free protons. Other small molecules can pass through the lysosome membrane, but will then become charged by picking up a free proton, then they are less likely to be able to leave the lysososome. A good reference on Lysosomes is at
 * http://cellbio.utmb.edu/cellbio/lysosome.htm

<< Golgi apparatus | Lysosomes | Peroxisomes >>

Cell Biology | Parts of the cell Organelles

title: Cell Biology/Lysosomes


text:
Cell Biology/Peroxisomes

Cell Biology | ../Parts of the cell/ | ../Organelles/

<< Lysosomes | Peroxisomes | Cytosol >>

It used to be thought that peroxisomes are formed by the budding of smooth Endoplasmic Reticulum (ER). However, now it is thought that they form through self-assembly. (I will get more information references as I do some more thorough literature searches). The peroxisome is another major source of Oxygen utilization (along with the mitochondrion). There are specific proteins associated with the peroxisomes membrane, also there are 3 oxidation enzymes associated with peroxisomes:

 * 1) D-amino acid oxidase
 * 2) Urate Oxidase
 * 3) Catalase

The enzyme contents vary with various types of cells. One of the main functions of peroxisomes in liver cells is detoxification. This is done by the oxidation of substances like:

 * 1) Alcohol - About 1/2 of the ethanol one drinks is converted to acetaldehyde by oxidation.
 * 2) Phenols
 * 3) Formic acid
 * 4) Formaldehyde

Why peroxisomes are not like lysosomes
Peroxisomes are organelles that contain oxidative enzymes, such as D-amino acid oxidase, urate oxidase, and catalase. They may resemble a lysosome, however, they are not formed in the Golgi complex. Peroxisomes are distinguished by a crystalline structure inside a sac which also contains amorphous gray material. They are self replicating, like the mitochondria. Components accumulate at a given site and they can be assembled into a peroxisome. They may look like storage granules, however, they are not formed in the same way as storage granules.

Peroxisomes function to rid the body of toxic substances like hydrogen peroxide, or other metabolites. They are a major site of oxygen utilization and are numerous in the liver where toxic byproducts are going to accumulate.

The peroxisome is made as a phospholipid bilayer, encapsulating oxidative materials. They would be 'sphere-ish' in shape, not necessarily a perfect sphere, and sometimes, they may take other shapes. But most electron micrographs I have seen (2 dimensions) show them as circles. (As you may be aware, the Cell membrane is also a phospholipid bilayer.) Peroxisomes have membrane proteins that are critical for peroxisomal function, to import proteins into their interiors, proliferate or segregate to daughter cells (This update, thanks to Babich Temps). The main differences would be:

 * 1) Types of phospholipids used.
 * 2) Size of the membrane (i.e. peroxisomes are MUCH smaller than the cell).

<< Lysosomes | Peroxisomes | Cytosol >>

Cell Biology | ../Parts of the cell/ ../Organelles/

title: Cell Biology/Peroxisomes


text:
Cell Biology/Cytosol

Cell Biology | ../Parts of the cell/ | ../Organelles/

<< Peroxisomes | Cytosol | Cytoskeleton and Microtubules >>

The cytosol (as opposed to cytoplasm, which also includes the organelles) is the internal fluid of the cell, and a large part of cell metabolism occurs here. Proteins within the cytosol play an important role in signal transduction pathways, glycolysis, and act as intracellular receptors and ribosomes. In prokaryotes, all chemical reactions take place in the cytosol. In eukaryotes, the cytosol contains the cell organelles. In plants, the amount of cytosol can be reduced due to the large tonoplast (central vacuole) that takes up most of the room of the cell.

The cytosol is not a "soup" with free-floating particles, but highly organized on the molecular level. The cytosol also contains the cytoskeleton. It is made of fibrous proteins and (in many organisms) maintains the shape of the cell, anchors organelles, and controls internal movement of structures, e.g., transport vesicles.

As the concentration of soluble molecules increases within the cytosol, an osmotic gradient builds up toward the outside of the cell. Water is flowing into the cell, making it larger. To prevent the cell from bursting apart, molecular pumps in the plasma membrane, the cytoskeleton, the tonoplast or a cell wall (if present) are used to counteract the osmotic pressure.

<< Peroxisomes | Cytosol | Cytoskeleton and Microtubules >>

Cell Biology | ../Parts of the cell/ | ../Organelles/

title: Cell Biology/Cytosol


text:
GCSE Science/Advanced static electricity topics

GCSE Science/Electricity

Before reading this module check to see if you need to. If you intend to take the foundation paper, you may find that you do not need to do the work on this page. If in doubt check with your teacher.

Where charge concentrates
When an object is charged up with electrons, the electrons try to spread out over the object to be as far apart as possible. This means they go to the surface rather than spread throughout. On a metal object the material of which the object is made shields the electrons from one another. They do not ‘’see’’ the electrons round the back. This means that highly curved objects can hold more electrons than flat objects. For a complicated shape, the electrons tend to congregate on the more highly curved areas, and to desert the flatter areas.

Inducing charge separation on neutral objects
Consider a crystal of gold for example. {This argument works for all materials}. Normally the atoms are perfectly spherical, and completely neutral.

Q1) Why are the atoms neutral?

Remember that neutral atoms contain positive charges in the nucleus and negative electrons orbiting in their shell. Normally the center of the positive charges and the center of the negative electrons is in the same place: the exact center of the atom. If we bring up a charged object to them however, something important happens. Look at the diagram on the right.

Q2) What would happen if we brought up a positively charged rod?

There is always an attractive force between the rod and the crystal no matter what the charge on the rod.

To see why this is so, we need to know one more thing about electrostatics. The force of repulsion or attraction falls off with distance. In fact, rather like gravity it falls off as the square of the distance. This means if you go to twice the distance the force becomes only a quarter as much. If you go three times the distance it becomes only one ninth as great and so on. Now look at the diagram again. The negative charges in the atoms are repelled by the rod, the positive ones are attracted, but the positive charges are closer, so overall there is a force of attraction.

Q3) Repeat the above argument with a positively charged rod to convince yourself that there is still an attractive force.

Lightning
Lightning is basically a great big spark. In a thunderstorm, separation of charge occurs in big rain clouds. No one is really sure of how this occurs, although it appears to be caused by ice crystals rubbing together and becoming charged. but what is known is that storm clouds have a negative bottom and a positive top. The bottom of the cloud is nearer to the ground so it induces a positive charge on the ground. When the voltage becomes high enough a spark flies between the cloud and the earth; this is lightning. The spark is so hot, it causes the air to rapidly expand then collapse; this causes thunder.

Q4) Why does the voltage need to be very high before lightning can occur?

Lightning rods
Lightning rods are used to protect buildings from lightning strikes. They are usually made from a length of copper rod with a pointed end. They are attached to tall buildings and the lightning strikes them rather than the building itself.

Q5) Why do you think the rods are made of copper rather than iron which is cheaper?

Q6) Why do the rods have a pointed end?

Q7) It is standard advice that if caught out in a storm you should never stand under a lone tree. Why is this advice good?

Answers | <>


text:
Geometry

Welcome to the Wikibook of GEOMETRY

Preface
The word geometry originates from the Greek words (geo meaning world, metri meaning measure) and means, literally, to measure the earth. It is an ancient branch of mathematics, but its modern meaning depends largely on context. Geometry largely encompasses forms of non-numeric mathematics, such as those involving measurement, area and perimeter calculation, and work involving angles and position. It was one of the two fields of pre-modern mathematics, the other being the study of numbers. In modern times, geometric concepts have been generalized to a high level of abstraction and complexity, and have been subjected to the methods of calculus and abstract algebra, so that many modern branches of the field are barely recognizable as the descendants of early geometry. This Wikibook is dedicated to high school geometry and geometry in general.

High School Geometry
The outline of topics reflects the California curriculum content standards.

General Geometry
Geometrie Géométrie Geometria מתמטיקה תיכונית/גיאומטריה אוקלידית 幾何学

title: Geometry


text:
User:Theresa knott

The same Theresa Knott as here

My home page

At the moment I am working mainly on the wikijunior project. I have also finished the GCSE electricity and magnetism book.

User:Theresa knott/sandbox

School Computer Club
The following girls are my pupils. Please let me know if you have any problems with them.

User:Flower(Knott)

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links
http://www.chemicroc.com/ChemiCroc.swf http://www.bbc.co.uk/schools/ks3bitesize/flash/sci_ani_15.swf http://www.scienceunleashed.ie/Games/States%20of%20Matter.swf http://ecokids.earthday.ca/pub/eco_info/topics/frogs/chain_reaction/assets/flash/chain_reaction.swf http://www.sciencelessons.co.uk/flash/chain.swf http://game.gprime.net/media/game/magnetism.swf http://www.mystery-productions.info/hyper/Hypermedia_2003/Johns/export.swf

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title: User:Theresa knott


text:
C Programming/Memory management

In C, you have already considered creating variables for use in the program. You have created some arrays for use, but you may have already noticed some limitations:
 * the size of the array must be known beforehand
 * the size of the array cannot be changed in the duration of your program

Dynamic memory allocation in C is a way of circumventing these problems.

The function
The standard C function  is the means of implementing dynamic memory allocation. It is defined in stdlib.h or malloc.h, depending on what operating system you may be using. Malloc.h contains only the definitions for the memory allocation functions and not the rest of the other functions defined in stdlib.h. Usually you will not need to be so specific in your program, and if both are supported, you should use , since that is ANSI C, and what we will use here.

The corresponding call to release allocated memory back to the operating system is.

When dynamically allocated memory is no longer needed,  should be called to release it back to the memory pool. Overwriting a pointer that points to dynamically allocated memory can result in that data becoming inaccessible. If this happens frequently, eventually the operating system will no longer be able to allocate more memory for the process. Once the process exits, the operating system is able to free all dynamically allocated memory associated with the process.

Let's look at how dynamic memory allocation can be used for arrays.

Normally when we wish to create an array we use a declaration such as

Recall  can be considered a pointer which we use as an array. We specify the length of this array is 10 s. After , nine other integers have space to be stored consecutively.

Sometimes it is not known at the time the program is written how much memory will be needed for some data; for example, when it depends upon user input. In this case we would want to dynamically allocate required memory after the program has started executing. To do this we only need to declare a pointer, and invoke  when we wish to make space for the  elements in our array, or, we can tell   to make space when we first initialize the array. Either way is acceptable and useful.

We also need to know how much an int takes up in memory in order to make room for it; fortunately this is not difficult, we can use C's builtin  operator. For example, if  yields 4, then one   takes up 4 bytes. Naturally,  is how much memory we need for 2  s, and so on.

So how do we  an array of ten  s like before? If we wish to declare and make room in one hit, we can simply say We only need to declare the pointer;  gives us some space to store the 10  s, and returns the pointer to the first element, which is assigned to that pointer.

Important note!  does not initialize the array; this means that the array may contain random or unexpected values! Like creating arrays without dynamic allocation, the programmer must initialize the array with sensible values before using it. Make sure you do so, too. (See later the function  for a simple method.)

It is not necessary to immediately call  after declaring a pointer for the allocated memory. Often a number of statements exist between the declaration and the call to, as follows:

A more practical example of dynamic memory allocation would be the following:"Given an array of 10 integers, remove all duplicate elements from the array, and create a new array without duplicate elements (a set)."A simple algorithm to remove duplicate elements: Because the length of our new array depends on the input, it must be dynamically allocated: The above array will currently contain unexpected values, so we must use  to set our dynamically allocated memory block to the new values:

Some security researchers recommend always using calloc(x,y) rather than malloc(x*y), for 2 reasons:
 * Many implementations of calloc carefully check the x and y arguments and return NULL if "x*y" could overflow. Using malloc(x*y), the multiplication "x*y" can overflow to 0 or some other too-small number, usually leading to buffer overflow.
 * calloc ensures that the buffer is completely empty of sensitive information, avoiding some kinds of security bugs (but, unfortunately, this would not have prevented the Heartbleed bug).

Error checking
When we want to use, we have to be mindful that the pool of memory available to the programmer is finite. Even if a modern PC will have at least an entire gigabyte of memory, it is still possible and conceivable to run out of it! In this case,  will return. In order to stop the program crashing from having no more memory to use, one should always check that malloc has not returned  before attempting to use the memory; we can do this by

Of course, suddenly quitting as in the above example is not always appropriate, and depends on the problem you are trying to solve and the architecture you are programming for. For example, if the program is a small, non critical application that's running on a desktop quitting may be appropriate. However if the program is some type of editor running on a desktop, you may want to give the operator the option of saving their tediously entered information instead of just exiting the program. A memory allocation failure in an embedded processor, such as might be in a washing machine, could cause an automatic reset of the machine. For this reason, many embedded systems designers avoid dynamic memory allocation altogether.

The function
The  function allocates space for an array of items and initializes the memory to zeros. The call  allocates   objects, each of whose size is sufficient to contain an instance of the structure. The space is initialized to all bits zero. The function returns either a pointer to the allocated memory or, if the allocation fails,.

The function
The  function changes the size of the object pointed to by   to the size specified by. The contents of the object shall be unchanged up to the lesser of the new and old sizes. If the new size is larger, the value of the newly allocated portion of the object is indeterminate. If  is a null pointer, the   function behaves like the   function for the specified size. Otherwise, if  does not match a pointer earlier returned by the ,  , or   function, or if the space has been deallocated by a call to the   or   function, the behavior is undefined. If the space cannot be allocated, the object pointed to by  is unchanged. If  is zero and   is not a null pointer, the object pointed to is freed. The  function returns either a null pointer or a pointer to the possibly moved allocated object.

The function
Memory that has been allocated using,  , or   must be released back to the system memory pool once it is no longer needed. This is done to avoid perpetually allocating more and more memory, which could result in an eventual memory allocation failure. Memory that is not released with  is however released when the current program terminates on most operating systems. Calls to  are as in the following example.

free with recursive data structures
It should be noted that  is neither intelligent nor recursive. The following code that depends on the recursive application of free to the internal variables of a struct does not work.

The statement " " will not free, causing a memory leak. The correct way is to define a function that frees every node in the data structure:

Because C does not have a garbage collector, C programmers are responsible for making sure there is a  exactly once for each time there is a. If a tree has been allocated one node at a time, then it needs to be freed one node at a time.

Don't free undefined pointers
Furthermore, using  when the pointer in question was never allocated in the first place often crashes or leads to mysterious bugs further along.

To avoid this problem, always initialize pointers when they are declared. Either use  at the point they are declared (as in most examples in this chapter), or set them to   when they are declared (as in the "delayed allocation" example in this chapter).

Write constructor/destructor functions
One way to get memory initialization and destruction right is to imitate object-oriented programming. In this paradigm, objects are constructed after raw memory is allocated for them, live their lives, and when it is time for them to be destructed, a special function called a destructor destroys the object's innards before the object itself is destroyed.

For example:

title: C Programming/Memory management


text:
Talk:Japanese/Grammar/Verbs

Untitled
There are several errors on this page, and I also don't quite like the approach to that is taken here. I think we should use the real names of the types of Japanese verbs, namely Itidan and Godan. Also, I am a big fan of Kana. Romanisatons are only crutches. This is also why I use the official Japanese romanisation, and not the Hepburn one if I have no access to a Kana-enabled PC. It's a bit slower in the beginning, but there's nothing better than Kana to learn Japanese.

Basically, apart from the irregular verbs, japanese verbs can be conjugated in all possible forms, based upon five basic stems, namely the dictionary form, and four forms derived from it. -masu is in fact an auxilliary verb wtih a (slighlty) irregular verb.

To explain it with an example:

hanasa: Informal negative stem. Used to form negative and passive forms. hanasi: Informal positive stem. Used to form more complex forms of the verb such as the polite forms, the informal past and the -te form. hanasu: Informal positive present form, also called dictionary form. hanase: Imperative stem. Used to form provisional and imperative forms. hanaso: Volitional stem. Used only to form the volitional.

Other example for godan (sinu=to die) sina (-nai, -nareru, -nasu, -naseru) sin (-de, -da, -dai, sinu sine (-ba) sino (-o)

And, for ichidan: tabe tabe taberu tabe tabe

Now, it should be clear why verbs are called "one-rank" (itidan) or "five-rank" (godan) in Japanese ^_^. —The preceding unsigned comment was added by 157.193.202.83 (talk • contribs) 02:31, 2 September 2003.

 * Suggestion implemented. If anyone else notices something out of place, feel free to comment.  覚えてください私は外人です.  :P  -- Emperorbma 04:28, 18 Oct 2003 (UTC)

There are several verbs with slight irregularities that aren't covered here. aru -> nai instead of *aranai, kureru -> kure instead of *kurero in the imperative, iku -> itte instead of *iite in the conjunctive, the one-kanji + suru verbs than sometimes conjugate like X-su instead of X-suru-- aisuru -> aiseru instead of *ai-dekiru (and can sometimes be X-zuru instead of X-ziru), and the five polite verbs irassyaru, ossyaru, kudasaru, gozaru, and nasaru whose stem is irregular and involves dropping the -ru instead of just the -u and adding "i"-- i.e. irassyaimasu instead of *irassyarimasu. —The preceding unsigned comment was added by 128.253.136.126 (talk • contribs) 16:52, 23 November 2004 (UTC)

I would like to point out that it would be helpful to others if the tenses were to be outlined in the context of proper usage and English equivalents (if any). Many may not feel they know enough to distinguish between the use of the "non-past" and the "volitative". Of course, those studying should know that the indicative can be formed by just using the infinitive (in some cases). Tenses are used in polite speech for the most part (?). —The preceding unsigned comment was added by 207.162.163.19 (talk • contribs) 07:40, 11 May 2004 (UTC)

Comments on the various moods like potential, passive, causative, etc. would also be nice. Also the other type of conditional -tara form and the representative listing -tari form. —The preceding unsigned comment was added by 128.253.136.126 (talk • contribs) 16:52, 23 November 2004 (UTC)

As an intermediate-level student of Japanese (I've taken five semesters, one of them in Tokyo), I must say this page confuses me, and I can't imagine a beginner, using this wikibook to teach themselves, learning anything from this. It reads more like a linguistic analysis than a step-by-step teaching process. Personally, I've never been a big fan of complex linguistics terms like "perfective," "conjunctive," and "euphony"; they don't serve to add to understanding, and probably confuse and scare away readers/students. Other terms like "conditional," "volitional," and "non-past" are, I think, a little better, as their meanings are more well-known and transparent. Still, even though the basic 'non-past' form (e.g. 食べる or 食べます) is used for both present and future, and as the infinitive, I've always seen it described as the 'present' tense, because this is simpler, and easier for a beginning student to wrap their mind around.

As for godan and ichidan, I've never heard that before, and so it's confusing to me. I learned them as う-verbs and る-verbs ... but either way is better than one book I saw that called them Type I and Type II verbs, and didn't even call the irregulars 'irregular', just called them Type III.

 * I've seen that. The source I saw also had an ある-class, including ござる and 下さる, which acted like る verbs (even though they end in ある rather than える or いる) but with the addition of an い to the conjunctive form, e.g. くださいます. I kind of prefer that arrangement, as the other systems gloss them over or consider them another sort of irregular separate from the irregulars (despite the fact that they're regular when considered as a group). 69.109.176.230 07:07, 27 May 2005 (UTC) (gwalla)

I apologize to complain and criticize without going ahead and changing things, making you do the work or whatever, but, I think it'd be ruder to go and change things now that you've obviously sorted the whole thing out and put a lot of work into it yourself. If you'd like me to write (or help) on part of it, just drop me a message. Thanks.

LordAmeth 15:31, 31 Dec 2004 (UTC)

Oh, and if I could add one more thing. Spelling. し should be written 'shi', not 'si'. しゃ should be 'sha' not 'shya', and certainly not 'sya'. じょ should be 'jo' not 'jyo'. These sorts of incorrect romanizations, in my opinion, make the language look more strange and esoteric, and confuse beginners who might mistake 'sya', 'sha' and 'shya' for different characters, and worse, who might actually get the wrong idea about pronunciation.

LordAmeth 15:35, 31 Dec 2004 (UTC)

Some comments
I do realise that it has been months since the last comments were made here. However there are some things I'd like to say about what is said above:

 * Verbs, adjectives and adjectival nouns traditionally have six stems; however, for verbs, the language has evolved such that in modern usage, two of the forms almost always coincide, so it looks like there are only five for verbs.

 * It is quite standard to call the verbs godan, ichidan and "irregular" in English, together with the other standard of calling the first two types u and ru verbs. Japanese-author textbooks use the type I-II-III style more.  However, the "official" types are:

 * 1) 五段 godan
 * 2) 上一段 kamiichidan = the single-row conjugation verbs ending in iru
 * 3) 下一段 shimoichidan = the single-row conjugation verbs ending in eru
 * 4) カ行変格 kagyou henkaku = kuru
 * 5) サ行変格 sagyou henkaku = suru

The verbs usually called "irregular" in English are thus not really called "irregular" in Japanese, just "different from normal". This is because while a foreign learner typically does not learn further than the Japanese as used in modern times, when verbs from much older texts are considered, there are quite a few more types of verbs:

 * 1) 四段 yodan - which naturally became 五段 verbs as a consequence of the writing reform in 1946
 * 2) 上一段 kamiichidan - the dozen or so of them have stayed as 上一段 verbs
 * 3) 上二段 kaminidan - they have become 上一段 verbs
 * 4) 下一段 shimoichidan - the only 下一段 verb in the old times, 蹴る, became 五段
 * 5) 下二段 shimonidan - they have become 下一段 verbs (but uru/eru has kept a slightly modified shimonidan conjugation even in modern Japanese)
 * 6) カ行変格 kagyou henkaku - 来 ku (= modern くる kuru)
 * 7) サ行変格 sagyou henkaku - out of these, only す su (= modern する suru) survived into modern times.  One of these old verbs was おはす owasu, the "ancestor" of ござる gozaru
 * 8) ナ行変格 nagyou henkaku - 1) 死ぬ shinu (became 五段 in modern times; however many dialects have kept the henkaku type conjugations); 2) 往ぬ inu (fell into disuse only last century)
 * 9) ラ行変格 ragyou henkaku - verbs that ended in り ri: あり (= modern ある), をり (= modern おる) etc.

and the true "irregular verbs" are called 特別活用 tokubetsu katsuyou verbs, such as the endless variations on ござる (there are easily twenty of them, as it evolved from the original おはす owasu all the way to Edo period's gozaru), or a verb like さしも sashimo (which doesn't even end in a u or i sound), which conjugates like sashima, sashimou, sashimo, sashimo, sashimae, sashimae/sashime.

Irregularities in conjugations, such as in the verb くださる kudasaru, are noted, but otherwise they are classified as godan or ichidan verbs officially. ない nai, the word used when one wants to express the negative of ある aru, is actually an adjective. Hence ない has such forms as なき naki and なし nashi, while none of the other verbs ending in -ない have such forms. In addition, the negative stem for ある aru, i.e. あら ara, exists, and is used in other situations. As a historical side note, there was indeed a period when the あらない form was used, when the auxiliary verb ない nai itself was pretty new. (In the old days it was ず zu.)

As for romanisation, it is actually the standard in Japan to write し as si, write しゃ as sya, write ち as ti, etc. But as has been pointed out already, this is misleading in terms of pronunciation, so the rest of the world has happily ignored it. However, because of its official status, one can't really say it's wrong either...

-- KittySaturn 04:16, 26 Jun 2005 (UTC)

 * Also, an extra note about the terminology being too technical: the style of terminology such as u and ru verbs is indeed easy for beginners to understand; however this kind of terminology simply does not work at more advanced levels of Japanese learning, because soon there will be so many "exceptions" that nothing makes sense any more - su beki would be an "exception", osokare hayakare is another "exception", the grammar pattern -zaru wo enai is an "exception", and the n in iwan bakari, being not of a negative meaning, becomes totally inexplicable... when they in fact fit into the "complicated terminology" grammar structure well, and it is just that the basic terminology is incapable of describing. -- KittySaturn 04:29, 26 Jun 2005 (UTC)

Verb suffixes
To what point should verb suffixes be mentioned? Should a section be made to discuss them and list common ones? -- Retropunk (talk) 09:38, 28 January 2009 (UTC)

 * I think it would be fine to make this page as exhaustive as possible. The reader can choose what to pick from it while the actual lesson pages should (in my view) take smaller steps and lead the reader along topics of increasing difficaulty. --Swift (talk) 10:38, 28 January 2009 (UTC)
 * The problem with an exhaustive list is that it will become a conglomerate mess as items get added. Perhaps it'll suffice to make pages on the conjugations and then make a list of suffixes there, which could lead to other pages.  --Retropunk (talk) 00:20, 1 February 2009 (UTC)

 * Sorry, where are you thinking of putting the list of suffixes? Discussing them in detail on sperate pages sounds fair enough, though. --Swift (talk) 06:23, 1 February 2009 (UTC)

VLC icon
Why is the VLC icon there? It has nothing to do with multimedia. —The preceding unsigned comment was added by 74.92.11.121 (talk • contribs) 01:16, 3 April 2009 (UTC)
 * The icon is used for the tag. The licensing does not restrict its use to the VLC media player. --Swift (talk) 21:45, 2 April 2009 (UTC)

title: Talk:Japanese/Grammar/Verbs


text:
Abstract Algebra/Lattice theory

A lattice is a poset such that each pair of elements has a unique least upper bound and a unique greatest lower bound.

title: Abstract Algebra/Lattice theory


text:
GCSE Science/Electrolysis

[[GCSE Science/Electricity]]

Electrolysis is the decomposition of certain types of substance using electricity. The types of substance that can be split are ionic substances. This just means that they are made of charged ions rather than neutral atoms. {Remember that an ion is just an atom that has either a positive or negative charge}. An example of an ionic substance is common table salt sodium chloride. The sodium atom has a positive charge, the chlorine atom has a negative charge. It is usually written as Na+Cl-.

Q1) Check in a periodic table, what is the symbol for sodium: Na or Cl?

As you may already know if you've studied the Metals module, a salt is any substance made by combining an acid with an alkali. Acids, alkalis, and therefore all salts are ionic.

Q2) Which of the following substances can be broken up by electricity: sodium chloride, iron sulphate, copper nitrate?

Basic experimental setup
Most ionic compounds are not liquid at room temperature. This is a problem because the ions need to be able to move for the electric current to be able to flow. This can be achieved by melting. Look at the electrical setup shown on the right. The electrodes are just two carbon rods connected to a battery. The one connected to the positive electrode is called the anode. The one connected to the negative electrode is called the cathode. this is due to a collision

Consider for example the compound lead bromide. This compound is a solid at room temperature but can be molten over a Bunsen flame. So what you would do is put some lead bromide into a beaker. Put the beaker on a tripod over a bunsen flame. Melt the lead bromide, then put in the electrodes and turn the power supply on at a setting of, say, 2V. What you would see happening is the cathode, is a silvery coating of pure lead forming, and bromine forming at the anode. The current would continue to flow until all the lead bromide was turned into lead and bromine.

Q3) It takes energy to split up a compound like lead bromide. Where does this energy come from?  Q4) Predict what products you would get at the anode and cathode if copper chloride was the electrolyte.

What happens at the anode
The anode is the positive electrode; it attracts negatively charged ions, because unlike charges attract. The bromine ions move through the melt until they reach the anode. Once they get there, they give up their two extra electrons to become bromine atoms.

2Br- → Br2 + 2e-

The electrons flow up the anode to the positive terminal of the battery.

What happens at the cathode
The cathode is the negative electrode; it attracts the positively charged ions. Metal ions are always positive and so the lead ions flow through the metal uhe negatively charged terminal of the battery and onto the lead ions.

Some trick to remember cations and anions, cathodes and anodes.

I have a cat......I call her by saying come here plussy! - cathodes attract positive ions

ca+ions has a plus in it, cations are positive ions

red cat: reduction occurs at the cathode

Pb2+ + 2e- → Pb

Q5) Solid ionic substances do not conduct electricity and are not split up by it. Why do you think that is?

Quantity calculations (higher tier only)

In the experiment with lead bromide, you saw that lead was deposited at the cathode. If you actually do the experiment you will see that the lead coats the cathode. In this section we will look at how much metal will coat a cathode in a given time.

A scientist performed the following experiment.
 * A copper cathode was carefully cleaned and accurately weighed.
 * It was placed along with an anode into a solution of copper sulphate.
 * It was connected via an ammeter to a variable power supply.
 * A current was left to run for a given time, then the cathode was removed and weighed again.

His results were:

You can see from the results that the total amount of copper deposited depends on both the current and the time it flows. This is because the number of copper atoms that can be made from ions depends on the total amount of charge that flows. The unit of charge is the coulomb.

One coulomb is the amount of charge when one Ampere flows for one second.

Q6) Look at the results table above. How much copper is deposited when 1A flows for 3000 seconds?

Q7) How much copper do you predict would be deposited if 1A were to flow for 6000 seconds.

Q8) What about if 2A were to flow for 12000 seconds ?

Electrolysis of Aqueous solutions (Advanced)
Before studying this section check with your teacher to see if you need to.

Earlier on in this module you've learned that ions must be able to move in order for electrolysis to work. If the ions are held rigid {such as in a solid}, they can't move and no electricity will flow. We've looked at how the freeing up of ions can occur by melting the electrolyte. Another way to achieve this is by dissolving the electrolyte in water. The trouble with this method is, there will be more than one type of ion present.

Water partially splits up into ions {this is why it's such a good solvent for ionic compounds}. It splits into hydrogen ions and hydroxide ions.

H2O → H+ +OH-

So at the cathode there will be two ions present: the metal ion and the hydrogen ion from the water. Which element is actually produced at the cathode depends on how reactive the metal is. If the metal is very reactive, such as potassium or sodium, then it is unlikely to be discharged. Hence hydrogen will be produced. If the metal is unreactive such as silver, the metal will be produced. To work out which ion "wins", the metal or the hydrogen, compare their reactivities in a the reactivity series. The one that is most reactive, will not be produced at the cathode.

A similar situation occurs at the anode. Hydroxide ions {from the water} are usually discharged at the anode ultimately producing oxygen. However, if the concentration of the ions of Halites (group 7) are much higher than that of the hydroxide ions, then the halite ions are discharged. Sulphates are never discharged.

OH- → OH + e-

4OH → 2H2O + O2.

Q9) Sodium chloride is dissolved in water and subjected to electrolysis. Explain what you see at each of the electrodes.

Answers | <>

title: GCSE Science/Electrolysis


text:
User:Yann

Hi,

I am from South-East of France, near Geneva.

Here I am mainly working on the LPI Linux Certification course. I also intent to help writing a Hindi and a Gujarati course.

Reminders

 * http://en.wikibooks.org/w/wiki.phtml?title=Special:Contributions&target=Attention-tunnel
 * /Talk orphaned

fr:Utilisateur:Yann hi:User:Yann w:en:User:Yann w:fr:Utilisateur:Yann

title: User:Yann


text:
Hindi

नमस्ते!

Hindi is an Indo-European language spoken as a first language in majority states in northern India and second language in many countries where these people have emigrated. It is written with the Devanagari, script which fairly closely follows the phonetics of the language. Spoken Hindi is very similar to spoken Urdu — as such they are both often classified as part of the Hindustani language.

Feel free to use Wiktionary's Hindi Category to study words.

Basic Hindi in 1,2,3 Steps
To be reorganized
 * /Basic Hindi/
 * /Everyday Phrases/
 * /Mini-tutorial Lesson/

 * 1: Introducing Hindi
 * 2: Speaking and Writing the Hindi language
 * 3: Your first pieces of vocabulary and grammar

Learning More

 * More on pronunciation
 * Extending your vocabulary
 * More useful grammar

Indepth Topics

 * Nouns
 * Verbs
 * Pronouns
 * Tenses

Glossary

 * Nouns
 * Verbs
 * Adjectives
 * Phrases and Idioms

title: Hindi


text:
Discrete Mathematics/Axiom of choice

Axiom of choice:

If $$f:A\rightarrow B$$ is a surjective map, then there exists a map $$g:B\rightarrow A$$ such that $$f\circ g$$ is the identity (trivial) map.

Lemma: Every set can be well-ordered.

title: Discrete Mathematics/Axiom of choice


text:
CACS/Glossary/ASProvider

An Application Service Provider (ASP) is a business model for delivery of business or IT services across a network. It may also be a service enterprise whose primary business is delivery of application services using the ASP model. ASP usually implies a central (vendor) data center that runs the application.

For further discussion, see the Wikipedia article.

title: CACS/Glossary/ASProvider


text:
Algebra/Equalities and Inequalities

Solving linear inequalities involves finding solutions to expressions where the quantities are not equal.

A number on the number line is always greater than any number on its left and smaller than any number on its right. The symbol "<" is used to represent "is less than", and ">" to represent "is greater than".

For example:

<--|-|-|-|-|-|-|-|-|-|-|->  -5    -4    -3    -2    -1     0     1     2     3     4     5

From the number line, we can easily tell that 3 is greater than -2, because 3 is on the right side of -2 (or -2 is on the left of 3). We write it as $$3>-2$$ (or as $$-2<3$$). We can also derive that any positive number is always greater than negative number.

Consider any two numbers, a and b. One and only one of the following statements can be true:
 * 1) $$a>b$$,
 * 2) $$a=b$$, or
 * 3) $$ay$$ and $$y>z$$, then $$x>z$$.

 * Additive property:
 * In an inequality, we can add or subtract the same value from both sides, without changing the sign (i.e. ">" or "<"). That is to say, for any three numbers $$x$$, $$y$$ and $$p$$, if $$x>y$$, then $$x+p>y+p$$ and $$x-p>y-p$$.

 * Multiplicative property
 * We can multiply or divide both sides by a positive number without changing the sign. For example, if we have any two numbers $$x$$ and $$y$$, and another positive number $$p$$, then if $$x>y$$, then $$x \cdot p>y \cdot p$$ and $$\frac {x} {p}> \frac {y} {p}$$.

 * When we multiply or divide both sides by a negative number, we have to change the sign of the inequality (i.e, ">" change to "<" and vice versa). So if we are given two numbers $$x$$ and $$y$$, and another negative number $$p$$, then if $$x>y$$, $$x \cdot p<y \cdot p$$ and $$\frac {x} {p}< \frac {y} {p}$$.

Now we can go on to solve any linear inequalities.

Solving Inequalities
Solving inequalities is almost the same as solving linear equations. Let's consider an example: $$x+4<13$$. All we have to do is to subtract 4 on both sides. We will then get $$x<9$$, and that is the answer! Note, however, what you get is not a single answer, but a set of solutions, i.e., any number that satisfies the condition $$x<9$$ (any number that is less than 9) can be a solution to the inequality. It is very convenient to represent the solution using the number line: <---o <-+-+-+-+-+-+-->  6     7     8     9     10    11

(Note: the open circle ("o") shows that the value 9 is not included in the solution set, as the inequality of this equation is less than 9, not less than or equal to 9. When we deal with less (greater) than or equal to (≤ or ≥) later on, we use a closed circle ("●") to show that the value is included in the solution set.)

Let us try another more complicated question: $$3x-2\ge2(x-3)$$. First, you may want to expand the right hand side: $$3x-2\ge2x-6$$. Then we can simply rearrange the terms so that all the unknown variables are on one side of the equation, usually the left hand side: $$3x-2x\ge-6+2$$. Hence we can easily get the answer: $$x\ge-4$$. This solution is represented on the number line below. Note that the solution requires a closed circle ("●"), because the $$x$$ is greater than or equal to 4. ●---> <-+-+-+-+-+-+--> -6    -5    -4    -3    -2    -1

Inequalities with a variable in the denominator
For example consider the inequality
 * $$\frac{2}{x-1}<2\,$$

In this case one cannot multiply the right hand side by $$(x-1)$$ because the value of x is unknown. Since x may be either positive or negative, you can't know whether to leave the inequality sign as $$<$$ (ie less than), or reverse it to > (ie greater than). The method for solving this kind of inequality involves four steps:
 * 1) Find out when the denominator is equal to zero.  In the above example the denominator equals zero when $$x=1$$.
 * 2) Pretend the inequality sign is an $$=$$ sign and solve it as such: $$\frac{2}{x-1}=2\,$$, so $$x=2$$.
 * 3) Plot the points $$x=1$$ and $$x=2$$ on a number line with an unfilled circle because the original equation included < (it would have been a filled circle if the original equation included $$\le$$ or $$\ge$$).  You now have three regions: $$x<1$$, $$12$$.
 * 4) Test each region independently.  in this case test if the inequality is true for $$1x>2)$$  (e.g. $$x=3)$$).  In this case the original inequation holds, and so the solution for the original inequation is $$1>x>2)$$.

Compound Inequalities
A compound inequality is a pair of inequalities related by the words and or or. In an and inequality, both inequalities must be satisfied. All possible solution values will be located between two defined numbers, and if this is impossible, the compound inequality simply has no solutions.

Consider this example: $$x+6\ge2$$ and $$x\le2$$. First, solve the first inequality for x to get $$x\ge-4$$. All and inequalities can be rewritten as one inequality, like this: $$-4\le$$$$x\le2$$ (write x between two ≤'s or <'s or both with the smaller number on the left and the larger number on the right). Now, we can graph this inequality on a number line as a line segment. Remember, all solutions to ≤ or ≥ must be graphed with closed circles. Interpret this graphic as "all numbers between -4 and 2, including -4 and 2." ●-● <-+-+-+-+-+-+--> -6    -4    -2     0     2     4

Now, let us consider or inequalities. Or inequalities usually do not have a set of solutions that satisfies both. Instead, they usually have two sets of infinite numbers that are solutions to each one. Because of this, or graphs define which numbers satisfy either equation. For example: $$x\;<1$$ or $$x-1\ge2$$. First, solve for x in the second inequality to get $$x\ge3$$. Now, graph the two inequalities on the same number line. Remember to use open and closed circles accordingly. <-o          ●> <-+-+-+-+-+-+--> -1     0     1     2     3     4

Solving Inequalities with Absolute Value
Since $$|x| = |-x|$$ A inequality involving absolute value will have to solved in two parts.

Solving $$|x-6| < 5$$

The first part would be $$x-6 < 5$$ which gives $$ x < 11 $$. The second part would be $$ -(x-6) < 5 $$ which solved yields $$x > 1$$.

So the answer to $$|x-6| < 5$$ is $$1<-● <-+-+-+-+-+-+-+-+-+-+-+-+-+-->  0     1     2     3     4     5     6     7     8     9     10    11    12

Graphing Linear Inequalities
The graphing of linear inequalities is very similar to the graphing of linear functions. A linear inequality is written in

Previous: Solving equations Next: Quadratic functions

title: Algebra/Equalities and Inequalities


text:
Talk:Japanese/Vocabulary/Everyday Phrases

Evening

 * こんばんは - Konban wa - Good evening.
 * おやすみ - Oyasumi - Good night.
 * おやすみなさい - Oyasumi nasai - an emphatic "Good evening".

Oyasumi - good night and oyasumi nasai - good evening is it correct?

Matusz 11:27, 7 Oct 2003 (UTC)

 * Sorry for the late reply..
 * Oyasumi & Oyasumi nasai are the same, meaning good night (or literally "please rest"), only that the latter is more polite.
 * And konbanwa is good evening. Tomos 21:19, 20 Oct 2003 (UTC)

 * Eh my typo on that, gomen ne? ^_^;; -- Emperorbma 07:04, 21 Oct 2003 (UTC)

Is it true that すみません means both thank you and excuse me? Also, there seems to be Dōmo missing in the transkription of どうもすみません (section "Please and Thank You"). --62.203.232.241 14:23, 14 Nov 2004 (UTC)

Missing
Could somebody add in an explanation for the past tense variations? Like in 200.34.166.34 18:19, 3 January 2006 (UTC)
 * doumo arigatou gozaimashita vs doumo arigatou gozaimasu
 * sumimasen deshita vs sumimasen

 * Alright, doumo arigatou gozaimashita is little too polite to say. Unless brown-nosing is the case.  You would simply say doumo arigatou- or you would say arigatou gozaimashita.  Likewise for the present tense form.  A rule of thumb here is the difference between shita (which is pronounce shta, unless talking to someone of high status then you will need to bust out shi-ta) and the masu only endings.
 * Masu is the present tense of a verb. For instance nani wo shimasu. Nani is the japanese for what when used to describe the object of a verb- wo is a particle used to indicate that the verb is going to be the next thing said- and shimasu( the present form of the verb).
 * Now in order to say something was doing in the past simply put shimashita. notice shimasushita.
 * Gozaimasu, indicating great thanks for something will be gozaimasushita in past tense form.
 * I would type more but it really is late and I just happened to be on :-).
 * Anata ha naze besuto tsukusanai desuka? —The preceding unsigned comment was added by 70.178.16.196 (talk • contribs) 07:05, 29 September 2007.


text:
JLPT Guide/JLPT N5 Kanji

JLPT Level N5
The following is a list of 81 kanji, which is most of the kanji necessary to pass the N5 level of the Japanese Language Proficiency Test (JLPT), prior to the updating of the list several years ago.

There are now 103 kanji in the level N5 exam (24 more than the kanji listed below). Kanji used in the N5 test are used in more difficult levels, too.

As of 2010, the JLPT no longer publishes an official vocabulary list. Unofficial lists for all JLPT levels are however published on.

title: JLPT Guide/JLPT N5 Kanji


text:
CACS/Glossary/ASP

Active Server Pages (ASP) (Microsoft, Web) is a technology that creates dynamic Web Pages by executing Java Script or VB Script statements on a server, generating HTML, and sending the resulting Webpage to a browser. ASP is packaged as a part of the Personal Web Server (PWS) and Internet Information Server (IIS) suites.

title: CACS/Glossary/ASP


text:
Computer Programming/MacOS Programming

About the platform
macOS is the primary operating system for the Macintosh computer. It was originally a system designed privately by Apple Inc, however with Mac OS X, it has been based on Unix. Specifically, a modified FreeBSD operating system called "Darwin".

There are many different kinds of software that can be developed for Mac OS X. People generally think of applications, but we'll briefly cover some of the other kinds.

Applications
Applications are what people generally think of when they think about software for Mac OS X. Cocoa applications include: Finder, Mail, Address Book, Safari, Microsoft Word, and Microsoft Excel. Anybody can develop applications using Apple's free development tools which includes XCode. Mac OS X applications are developed using Objective-C though there are other possible programming languages that could be used.

The most popular languages for use on the macOS platform is Objective-C which could be thought of as Mac OS X's "native language" since the Mac OS X libraries, or "frameworks", all have an Objective-C interface. Objective-C includes everything that plain C can do, and adds object-oriented programming. See: Objective-C.

C++ can be used in developing for the Mac, but generally, it is used in addition to Objective-C rather than being in place of Objective-C. Using both Objective-C and C++ is called "Objective-C++" and is considered to be optional when developing software for Mac OS X: C++

See Programming:Objective-C for a lesson on the basics of Objective-C may also be of assistance.

Some preliminary thoughts:

Objective-C is the language most commonly used in Mac OS Programming. Objective-C entered Mac OS X and has ancestry in NeXT. Cocoa. Before you learn Mac programming you must  know the basics of C since it is the basis for Objective-C.

There used to be three separate APIs for developing a Mac application with a GUI:

1. Classic (Mac OS 9 and lower). Developing for the Classic API is no longer done. When Mac OS X first came out, users and developers had a huge investment in software written for Mac Classic OS and Mac OS X used to have an emulation mode so that users could run their old software. Apple has long since stopped support of the Classic API and Classic emulation in Mac OS X.

2. Carbon (Mac OS 8.5 up to and including Mac OS X 10.6 Snow Leopard). Carbon was an API for developers to update their applications that used the Classic API to be run without the Classic emulator. Carbon was a great way that Apple provided developers to upgrade their software to run on Mac OS X without having to totally rewrite their software, but Carbon, like Classic, is no longer supported by Apple.

3. Cocoa (All versions of Mac OS X). Cocoa is the most native API that can be used to develop applications for Mac OS X that are truly "Mac-like". Generally, Objective-C will be used along with Cocoa, though there are other options such as Cocoa-AppleScript and Cocoa-Python, but Cocoa-Objective-C is really the "mainstream" way to develop Cocoa applications.

Resource Forks Files in Mac OS X have a feature that is unique to Mac OS and that is that each file on disk can have two "forks". This feature used to be used for Classic and Carbon applications to separate code from resources (such as menus, windows, etc.), and the Mac OS X file system still supports two forks, but you should only use the "data fork". The resource fork is non-standard and can be lost when transferring Mac files to other file systems.

AppleScripts
Another "native language" for developing Mac OS X applications is AppleScript. AppleScript is a language that Apple invented to automate repetitive tasks. The AppleScript application is located on your Mac at /Applications/Utilities/AppleScript Editor. AppleScript can be used to record AppleEvents, the events that applications send to themselves or to other applications. Why don't you try it out. Open AppleScript Editor, press the record button, do some things with your other applications and watch the script write itself. AppleScript can be used alone or it can be used along with XCode to develop Cocoa Applications using mostly AppleScript instead of Objective-C. This option is mostly for experienced AppleScript programmers who don't know Objective-C.

Automator Workflows
Apple also provides an application called "Automator" that can be used to easily automate repetitive tasks. It is located at /Applications/Automator.app

Shell Scripts
Mac OS X has an application called Terminal that provides a command-line interface to Mac OS X. It is possible to develop scripts for the command line. Terminal.app is located at /Applications/Utilities/Terminal.app To create a shell script, you need a text editor. There is a text editor that comes with Mac OS X called "TextEdit.app". It is located in /Applications/TextEdit.app. But actually, what is better than TextEdit is a program such as TextWrangler.app which is available for free from the following link: http://www.barebones.com/products/textwrangler/

The shell that Terminal.app uses by default is called "bash". Here is a simple tutorial on developing bash scripts http://www.maclife.com/article/columns/terminal_101_automate_terminal_bash_scripts

We won't go any more deeply into shell scripts here in this wikibook, but it's just good to know what they are. You can always google for more information now that you know what to google for.

Command Line Tools
When you open Terminal and you learn how to type in commands. The commands are usually command-line tools or scripts. Above, we just talked about developing your own scripts with a text editor. It's also possible to develop your own command-line tools, using XCode. This is an advanced thing to do. Usually, power-users will write a shell-script (or some other kind of thing such as an AppleScript or an Automator Workflow) but it's good to know what a command-line tool is. Command-line tools have a textual user-interface rather than a graphical user interface (GUI).

Java
Java used to be treated by Apple as a "first class language" to develop for Mac OS, however in recent years, Apple has less support for Java. Now with Mac OS X 10.7 "Lion" and 10.8 "Mountain Lion", Java doesn't even come pre-installed in Mac OS X. Java is still available, but users have to download Java from Oracle's website and install it themselves. Apple's Mac App Store doesn't even allow Java apps to be sold at their store calling Java "deprecated".

However, there still are Mac developers who use Java because it has the advantage of being cross-platform compatible. For example, the same source-code can be used to generate software that runs on Mac, Windows, and Linux.

Apple has said that Java reduces the Mac to the "least common denominator". That's why they support it less.

Python
Python is somewhat supported by Apple. In fact, Python is shipped with Mac OS X and is part of the System Folder. There are third-party libraries that allow developers to develop applications using Python and Cocoa together, but these are not very well maintained, and Python on the Mac is most suitable for developing command-line utilities, or cross-platform scripts that aren't really very Mac-like.

Ruby
Similar to Python.

Websites
Most Mac users use Safari for their web browser. Safari uses the standards set by w3c.org You can develop websites that work with Safari by following the standards of the w3c.org. Remember to validate your HMTL, CSS, and JavaScript.

HTML Validator: http://validator.w3.org/

CSS Validator: http://jigsaw.w3.org/css-validator/

JavaScript Lint: http://www.javascriptlint.com/online_lint.php

If you're developing websites using your Mac and using Safari, remember to test your webpages on other platforms and with other web browsers.

Mac OS X Specific Languages
Objective-C is really the "native" language for Mac OS X development

 * Objective C Programming

You could call AppleScript a "native" language too, but it isn't really used to make commercial applications. It was designed to be used by real power-users to automate their tasks. Although it is possible to use AppleScript to build Cocoa applications in XCode, this would be more for users who already know AppleScript and don't want to learn Objective-C.

 * Applescript Programming

Mac OS X Frameworks

 * Cocoa

title: Computer Programming/MacOS Programming


text:
CACS/Hardware Introduction

This part contains a survey of the world of computer hardware. This chapter introduces computer hardware and provides a very short history of computing. This section introduces the computing environment thrugh a brief history of computers and an overview of the subjects within hardware.

Outline of computer history
There is some disagreement about when the digital age began. After all, the Babylonians used a kind of abacus about 500 BC. If we call it the computer age, we can get a much cleaner mark. 1951 was a watershed year, and two events identify it as the beginning. The UNIVAC became the first commercially available digital computer. That same year a research team at MIT completed the first user-interactive computer (named Whirlwind) that used a keyboard and a television screen or CRT. Considering developments by decades gives a pretty clear picture of the evolution of computers.
 * 1950s the vacuum tube decade - introduction of computers and their use in business and major scientific research;
 * 1960s the mainframe decade - transistor-based computers used in business;
 * 1970s the PC decade - the first CPU on a chip to widely available personal computers;
 * 1980s the software decade - windows, games, and spreadsheets make the PC useful;
 * 1990s the internet decade - creation and then commercialization of the Web.

Vacuum tubes
computer hardware notes

Computer Hardware
All notes of Computer hardware

title: CACS/Hardware Introduction


text:
Talk:CACS/Hardware Introduction

I've posted one part of this module early, and I'm still working in it. The reason to do this is to promote dicussion and editing. The outline by decade, and the names assigned for each decade are NOT traditional or widespread. They are New material for this book.

Because they are new, I'd really like comments or suggestions from others. I need to find out if this structure (by decade) makes any sense, and welcome any ideas about better ways to summarize each decade. LouI 21:53, 3 Sep 2003 (UTC)

The trouble with decades is they are exactly 10 years long :-( You could try naming them eras or ages instead then you can divide things more natuarally. Theresa knott 08:02, 4 Sep 2003 (UTC)

title: Talk:CACS/Hardware Introduction


text:
User:Marshman~enwikibooks

I'm the same Marshman from the Wikipedia Project but presently not active.

Here at WikiBooks, I am interested in putting together a Study Guide on Botany and on on Ecology, by which I mean an outline of botanical or ecological subjects organized as they would be found in a textbook with links to appropriate Wikipedia articles (where I am working to instill botanical credibility). In time, text would need to be added to the Study Guide to introduce and transition between subjects. Eventually, this outline could be fleshed out into a textbook. Hopefully this approach will result in a useful product (although incomplete) much sooner than attempting to write a textbook from scratch.

I am a biologist with a background in marine biology, terrestrial botany, water quality, and ecology. I am still active in the work force as a biologist/consultant and own a 13-person consulting firm in Hawaii.

title: User:Marshman~enwikibooks


text:
Sanskrit

Sanskrit is an old Indo-Aryan language once spoken throughout India. Many poems, epics, and prayers are written in it. Although not widely spoken anymore, it gave rise to many of the modern languages of India and influenced several more languages that are not related to it; Sanskrit is also still used as a language of culture and religion in India.

In the past, Sanskrit was written in a variety of scripts by people from various places. Today, a modified version of the Devanagari script has been agreed upon as a standard.

General Sanskrit lessons

 * Introduction to Sanskrit
 * /Basic grammar/
 * /Nouns/
 * /Verbs/
 * /Pronouns/
 * /Adjectives/
 * /Sandhi/
 * Words and Phrases

Cultural

 * History
 * Culture
 * Clothing

Sanskrit script

 * Devanagari
 * Transliteration

Harvard-Kyoto coding
a A i I u U e ai o au aM aH (or a:) ka kha ga gha Ga (nasal "ng") ca cha ja jha Ja (nasal "ny") ta tha da dha na Ta Tha Da Dha Na (retroflex) pa pha (not "fa") ba bha ma ya ra la va ha A bb ah

Glossary

 * Nouns
 * Verbs
 * Adjectives
 * Numbers
 * Phrases and idioms

title: Sanskrit