text:
Polish/Questions

In Polish, sometimes yes/no questions are created by a rising tone, which is indicated by a question mark:
 * Basia ma kota - Basia has a cat.
 * Basia ma kota? - Does Basia have a cat?

However, this is more or less to the equivalent of saying in English: "Basia has a cat?"

Another way to form a question is by using the word 'czy'. This makes it slightly more formal and also easier to understand for foreigners.
 * Czy Basia ma kota? - Does Basia have a cat?

Specific questions are created by question pronouns like:
 * gdzie - where
 * kiedy - when
 * kto - who
 * co - what
 * ile - how many
 * jaka - what kind
 * która - which
 * jak - how
 * dlaczego - why
 * czyj - whose

"kto" and "co" behave like nouns (but they don't have number) and "jaka" and "która" like adjectives, so you must use them in their proper form.

A question pronoun is usually moved to the beginning of a sentence, even if it replaces something that would usually be at the end, like an object.

 * Kogo lubi Basia? - who does Basia like? (who in accusative and moved to beginning of sentence). Emphasis on "Basia"
 * Kogo Basia lubi? - also correct but emphasis on "to like"
 * Co pije dziecko? - what does a child drink? ("what" is in accusative), emphasis is on "dziecko"
 * Co dziecko pije? - also correct but emphasis is on "to drink"
 * Kogo lubisz? - Who do you like? ("who" is in the accusative)
 * Z kim rozmawiasz? - who are you talking with? ("who" in instrumental). "Rozmawiasz" - second person singular of verb "to talk".
 * O czym myślisz? - what are you thinking about? ("what" in locative)
 * Gdzie jest ciastko? - where is the cake?
 * Gdzie są dziewczyny? - where are the girls?
 * Którą dziewczynę lubisz? - which girl do you like? ("which" and "girl" in accusative)
 * Jaką pijesz kawę? - what kind of coffee do you drink? ("what kind" in accusative). May mean either "What kind of coffee are you drinking?" or "What kind of coffee do you like?" (and drink usually)

^ Polish ^ > Polish pronunciation >

title: Polish/Questions


text:
Polish/Verbs

There are two classes of verbs in Polish - perfective verbs to talk about actions that are completed or will be completed, and imperfective verbs for actions that are taking place in some moment (no indication of completion). Very often they form pairs.

Perfective verbs don't have a present tense - if something is already done you must use the past tense and if it's not - the future tense. This "future perfective" tense is identical in form to the present tense. Let's take the imperfective and perfective verbs for "to drink":
 * Kot pije mleko - "The cat drinks milk" or "The cat is drinking milk now", pije is an imperfective verb
 * Kot wypije mleko - "The cat will drink (all the) milk", wypije is a perfective verb

To form other tenses besides the present and future perfective we need two more verb forms - the infinitive and the participle.

The infinitive usually ends with "-ć". The participle depends on the subject's number and gender:

Very often a perfective verb is formed from the imperfective by some prefix. Another class of pairs is verbs which are already derived from some other verb by prefixing. In Polish double prefixing is very rare, so an alternative form of base verb is used with the same prefix.

Participles usually have regular endings showing the number and tense of the verb's subject: "ła", "ł", "ło", "li", "ły". In some cases "a" also changes to "e" in the plural person-masculine, where a softened consonant is used. This is one of the typical features of the Polish language, and it can also be found in other places, for example the locative of the noun "miasto" (city) is "mieście".

The future imperfective is formed by the future form of the verb "to be" (equivalent to "will" in English) and either the third person form of the participle or simply the infinitive. The participial form is more common, however, if you're unsure of the correct ending, just use the infinitive.

 * Basia będzie czytać książkę - Basia will be reading a book.
 * Basia będzie czytała książkę - also correct
 * Basia przeczyta książkę - Basia will read the (whole) book
 * Dziecko będzie jadło ciastko - "The child will be eating a cake", or "The child will eat part of cake" (it might eat the whole cake, but the sentence doesn't specify this)
 * Dziecko będzie jeść ciastko - also correct
 * Dziecko zje ciastko - the child will eat the (whole) cake
 * Zrobisz obiad? - will you make dinner? (question about effect or result, that is dinner. Contains implied expectation of completion of action)
 * Będziesz robić obiad? - will you make dinner? (question about action. No indication if dinner is expected to be completed)

You can also use the verb "to be" on its own:
 * Ciastko będzie smaczne - The cake will be tasty (the cake probably hasn't been made yet, but when it is made, it will be tasty)
 * Basia będzie mamą - Basia will be a mother (Basia is pregnant)
 * Adam będzie inżynierem - Adam will be an engineer (maybe he's studying engineering)

Past tenses - past perfective and past imperfective - were originally formed in a similar way, but later the auxiliary verb merged with the participle. The Polish past perfective doesn't have anything to do with the English perfect tense - it's used for completed actions and is more similar to the English simple past.

The participle alone is the correct third person past tense:

 * Basia zrobiła kawę - Basia made coffee (past perfective tense, important thing is that coffee is available now)
 * Basia robiła kawę - Basia was making coffee (past imperfective tense, answer for "what was Basia doing when you last saw her" or "what is all that mess in the kitchen". No indication if the action was completed.)

In first and second person you have to add:
 * First person singular - "m"
 * Second person singular - "ś"
 * First person plural - "śmy"
 * Second person plural - "ście"

Note that for the masculine singular ("-ł") you have to add an extra "-e-":
 * zrobiłem kawę - I made coffee (masculine I)
 * zrobiłam kawę - I made coffee (feminine I)
 * zrobiłeś kawę - you made coffee (singular masculine you)
 * zrobiłaś kawę - you made coffee (singular feminine you)
 * zrobiłyśmy kawę - we made coffee (... and we are all girls)
 * zrobiliśmy kawę - we made coffee (... and there is at least one man among us)

There is also a tense to mark something that happened before a given event in the past, like the English "pluperfect", but it's very archaic now and rarely used in modern Polish.

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

title: Polish/Verbs


text:
Polish/Usage of the infinitive

chcieć - to want lubić - to like umieć - can/to be able to potrzebować - to need
 * Past tense: chciał/a(sing. masc/feminine), chcieli/chciały (pl. masc/feminine)
 * Conjugation: chcę, chcesz, chce, chcemy, chcecie, chcą
 * Past tense: lubił/a(sing. masc/feminine), lubili/lubiły(pl.masc/feminine)
 * Conjugation: lubię, lubisz, lubi, lubimy, lubicie, lubią
 * Past tense: umiał/a, umieli/umiały
 * Conjugation: umiem, umiesz, umie, umiemy, umiecie, umieją
 * Past tense: potrzebował/a, potrzebowali/potrzebowały
 * Conjugation: potrzebuję, potrzebujesz, potrzebuje, potrzebujemy, potrzebujecie, potrzebują

You may use these verbs, and many others, together with other verbs in the infinitive:
 * Basia lubi pić kawę - Basia likes drinking coffee.
 * Basia lubi kawę - Essentially the same meaning, "drinking" is implied.
 * Dziecko lubi jeść ciastka - The child likes eating cakes
 * Dziecko lubi ciastka - and "eating" is the usual thing you do with cakes
 * Adam lubi myśleć o Agnieszce - Adam likes thinking about Agnieszka
 * Adam lubi Agnieszkę - Adam likes Agnieszka
 * Tomek chce być inżynierem - Tomek wants to be an engineer (or become an engineer)
 * Dziecko chce jeść - The child wants to eat (or The child is hungry)
 * Basia umie robić kawę - Basia knows how to make coffee
 * Kasia potrzebuje umieć jeździć samochodem - Kasia needs to be able to drive a car (Two infinitives stacked one after another, while car is in the instrumental)

^ Polish ^ > Polish pronunciation >

title: Polish/Usage of the infinitive


text:
Polish/Prepositions as hints to declensions

Prepositions as hints to declensions
Prepositions, which generally show some sort of literal or figurative relationship between events, very rarely overlap exactly between different languages, both in literal and figurative usages. For example, to a non-native English speaker, it is not obvious why we talk about something, rather than talk on, at, or in something.

The correspondence shown below between some key Polish and English prepositions should not be taken as a relation in terms of meaning (semantics); it is only a rough approximation.

However, in Polish, both the choice of verb and the preposition (the Polish preposition, of course) are constrained by the declension. Once you develop some intuition as to which preposition you should use, or which declension, the relation between these can be used to guess the declension from the preposition or vice versa. Common links are as follows.

Note that some prepositions, these regarding to place, can be used with two possible cases. Usually, a locative or instrumental are used when the acting takes place in this place and accusative when it is going towards the place. Compare:
 * Kot siedzi na stole. - The cat sits on the table. (table - locative)
 * Kot wskakuje na stół. - The cat jumps onto the table. (table - accusative)
 * Kot nie wskakuje na stół. - The cat doesn't jump onto the table. (table still in accusative, not genitive, because it is not an object here!)

 * siedzi - 3rd person sing. present tense from "siedzieć" - sit
 * stół - table (gen. stołu, loc. stole, pl.nom. stoły)
 * wskakuje - 3rd person sing. present tense from "wskakiwać" - jump on


text:
Talk:High School Mathematics Extensions/Mathematical Programming

(flattened this thread. Use horizontal rules between threads.) -- r3m0t 23:56, 7 Dec 2003 (UTC)

I'm glad you liked HSE so much! I'm trying my best to do a good job, but as so often is the case in my first drafts, glaring spelling and grammar mistakes seem to plague my work. Lucky you pick them out for me.

I do not know enough about Lisp, Prolog, Scheme (never heard of it) or Haskell to decide whether they are suitable for high school students or not. If you think a coherent course can be taught using one of those languages, then please go ahead! Create a new chapte if you have to. But I was thinking of teaching a more conventional language like Pascal. Anyway we are not just writing about programming, but mathematical programming. Haskell seems to be a good choice, but where can I find a good programming IDE/compiler for it? I simply haven't done the research.

And nice to meet you. How do you do?Xiaodai

 * Just being a stickybeak, but
 * If you want Haskell, the Glasgow Haskell Compiler is an excellent Windows/*nix based Haskell interpreter and compiler environment. Some systems may only run the Hugs system. I'm about to go to bed so I can't give you an exact link but I'm sure you can google it :)
 * Haskell is a good choice of language for pure, functional programming. It's not quite the best language for exploring mathematical concepts in since it's a strict functional programming language. You may want to concentrate on looking at programming in common Computer Algebra systems such as Maple and Mathematica (I do know both systems, but Mathematica's better) for stuff like numerical approximations and all that funky jazz. Haskell is nice for exploring recursion, but more conventional looping structures are easier taught in some other language. With teaching Mathematica (You guys should still have it at Sydney, right?) you get the best of both worlds, really.
 * HTH :) Dysprosia 11:59, 7 Dec 2003 (UTC)

 * Think free. Learn free. is the Wikibooks concept, but Mathematica seems to be a commercial thing. I wouldn't encourage people to use a propriety language on Wikibooks. Wikipedia: Lisp programming language Scheme programming language Haskell programming language Maple computer algebra system Mathematica Maxima Computer algebra system r3m0t 19:58, 7 Dec 2003 (UTC)

 * It doesn't mean we can't teach non-free software, at all. And it's not exactly proprietary software either - it's well used. I merely mention this to Xiaodai as an option. In any case, are we to forbid the creation of a Windows guidebook here because it is non-free software? We cannot be bigoted on the forbidding of teaching just because of its origins now, can we? Dysprosia 21:43, 7 Dec 2003 (UTC)

 * A Windows guidebook would be created for users of Windows who wish to (manipulate/configure/whatever) their installation. By teaching Mathematica in a textbook not created specifically for teaching Mathematica, that is encouraging people to use Mathematica. Lisp, Scheme, Ruby, Haskell seem different to me - it is hard to make any money out of them (plenty of compilers or interpreters are free already) so it's offering a choice of compiler, etc. r3m0t 21:55, 7 Dec 2003 (UTC)

 * That's fine, and I understand where you're coming from. However to simply restrict our choice of teaching tool because the product is commercial is not a necessarily good thing - Lisp, Scheme, Ruby and Haskell are fine programming languages, but they are just that -- programming languages. Haskell and other functional programming languages have mathematical groundings, but we aren't teaching lambda-calculus, we're teaching how to obtain numerical solutions to things. For this, Haskell and its ilk are not suited for this and an imperative language is better suited. Dysprosia 22:59, 7 Dec 2003 (UTC)

I think it's best not to use any commercial software, most high school students do not have access to them. The ideal choice would be something like Free Pascal, C++ or Java (something platform independent). Xiaodai

 * If you want to go down that path, C's your best choice. But to properly teach good C and not just C's nuts and bolts of C you really have to get into the details. I wouldn't suggest OO languages because it's just not necessary. Dysprosia 11:47, 8 Dec 2003 (UTC)

 * Agree 100%. Still think Pascal is a good choice though -- my first love. Let this be undecided until we decide to start writing it. Xiaodai

 * Pascal...not so sure on this one. I'll think of this some more, too. Dysprosia 12:24, 8 Dec 2003 (UTC)

 * We can't decide to start writing it until we decide what programming language to use! I think C is pretty complicated, with all the #includes and things before the code bulk. I prefer Scheme (simplified Lisp) because I can just type stuff in the top frame and execute it in the bottom. I could also type straight into the bottom. (I'm talking about DrScheme, which runs on Windows 95+, Mac OS Classic or X, and Linux). MzScheme, the core of DrScheme, can be run seperately. r3m0t 12:40, 8 Dec 2003 (UTC)

 * Okay, we know you like Scheme! :) C's not too complicated, really. It can be rote-taught. If one is trying to learn C proper it can be a bit more difficult.
 * The reason why I don't think Scheme is best here is because it's a functional programming language and is simply not best suited for performing certain tasks which this chapter will probably aim to try and tackle.
 * If you want to teach Scheme, why not start at Computer programming and start a new chapter? Dysprosia 12:48, 8 Dec 2003 (UTC)

 * I have no love for teaching any programming language proper, I don't think that's the way to learn programming. We will go into the practical aspects head first. And for that reason, I want to find a language with as few boiler-plates as possible. For C, we will only need #include and so I don't think that's a problem. As for Scheme, I haven't tried it yet(soon will). This is still a pretty much undecided matter.

 * On an aside note, I have soon come to realize that someone learning C by "osmosis", so to speak, means that they will only produce inefficient, buggy, and just plain bad code. Garbage in, garbage out, they say!... For reasons why this is so, I could write a short book, but anyway, that's beside the point :)
 * I was thinking we could teach GNU Maxima (I think the syntax is like Maple's), but I have no experience in Maxima whatsoever, yet I do with Maple, Mathematica and C.

R3m0t, you should wait till we have some sort of consensus on which language we are to use before we start writing the programming section here. We work by consensus at the Wikipedia, we should do so here. Dysprosia 02:01, 14 Dec 2003 (UTC)

 * I agree with Dysprosia on this one. Xiaodai

Teach C
We shall use C as the language for this chapter. Xiaodai 05:55, 14 Jul 2004 (UTC)

Heavy editing
I will have to heavily edit the intro to programming section, because i feel it has too many things that are potentially confusing and is giving to much irrelevant information to the reader. I want a minimalist approach to this chapter, we will not be attempting to teach the user how to program properly. They can read other materials if they want to do that. We want this chapter to have a mathematical focus, rather than a computer science/computing one. Xiaodai 06:02, 14 Jul 2004 (UTC)

Pseudocode?
It seems there has been a heated debate about which programming language to use, here's my two cents: Afterall, we're teaching the method of programming to study and explore mathematical problems, right? It's the technique, the algorithm that matters, not the programming language. Maybe we can use pseudocode here. And when later we've a majority opinion on which programming language to use specificlly, we can easily convert them back. --Lemontea 10:38, 12 August 2005 (UTC)

I think I've come up with a reasonable solution to this problem. Instead of choosing any one language why not use pseudocode in the body of the text, thus providing this information in a more general context in order to demonstrate how an algorithm might be written. Then near the end of the article, or after major examples a link can be given to a page where various code snippets from a variety of languages can be submitted for users to get a more specific example of a concept in the language they are comfortable with. This seems like it would solve any disputes and create a book that is not bounded by the constraints of teaching in any one language. Tell me what you all think. --Etscrivner 8:25, 27 November 2005 (UTC)

The Programming Language
If this is for High School Students, either an appropriate first programming language should be used or we should follow the AP Computer Science Standards. http://apcentral.collegeboard.com/apc/public/repository/ap08_compsci_coursedesc.pdf

AP Computer Science exam uses Java as their Language. That should a fine first language, but if others think that something easier should be used, than I would recommend using PHP. Or better yet, why not use PHP is relation to MediaWiki. Maybe this chapter's scope should be limited to how to setup a MediaWiki using PHP, MySQL, and Apache. For a project, pick a simple extension, it could even be one that is already written or just make one up that would be fun for a student to use. It is much easier to add onto an existing code base than to write something completely from scratch. The kids can be exposed to all of the basic programming structures, but actually accoplish something tangable at the same time.

I am a Software Engineer, and C is definitely NOT a first programming language. There is no safety in C, and it is very easy to get yourself into trouble really fast. Between PHP and Java, I personally feel that PHP is easier to learn, especially when it is the foundation language for many shareware products: MediaWiki, Moodle, WordPress, etc. So my final vote for a chapter in a high school math book, as opposed to a whole textbook is PHP. Zzmonty (talk) 05:15, 1 February 2009 (UTC)

The Case for Python
OK, here's my 2 cents worth on this issue. We should pick a language which allows students to focus on the algorithms without getting too involved in the nuts and bolts of software engineering.

C: is great for teaching people how computers actually work but is a bit too "close to the machine" to be ideal for teaching people how to use computer programs to explore mathematics. Students are likely to spend too much time on pointers, memory management and compilation/linking problems. Also the need to have separate header and source files is a distraction.

Java: is great for teaching OO programming but the fact that it is so Object Oriented means that students will have to spend too long getting to grips with Objects, Classes, Inheritence, Polymorphism etc. and not enough time thinking about the algorithms.

Lisp/Prolog etc: again are great for teaching predicate calculus but are difficult to use for purely functional programming.

Python: has a simple and consise syntax and scripts can be run directly without the need for the compilation stage. There is no need to consider pointers, type conversions, memory management etc. Likewise there is no need to be distracted by OO concepts but OO concepts can be introduced if needed. Also the interactive python shell can be used directly as a sort of massively powerful and expressive calculator. Also Python has the NumPy and SciPy modules that enable you to easily do graphs, statistics, linear algebra and much much more! Also it is free (as in beer) and Open Source....for what its worth my vote goes for Python.(Russell (discuss • contribs) 10:06, 19 July 2011 (UTC))

modulus examples
5%2 is 1 as far as I know ....--Billymac00 (discuss • contribs) 02:04, 26 September 2014 (UTC)


text:
Talk:Polish/Some useful expressions

Untitled
"Jak się masz" - how are you is unnatural phrase in Polish with different meaning compare to English. It is personal question, not greeting. IMO it can stay, but with cultural difference explanation and stressing that natives are not using it. --anon Pole 25.07.2017

Would "Dziękuję" be better translated as "thank you" (instead of the quite informal "thanks") to signify its (relative) formality? --Menchi 04:27, 8 Dec 2003 (UTC)

Generally "Dziękuje" means "thanks". When you are about to say "Thank You", you have to say "Dziękuje Ci" No!!! I'm from Poland. "Dziękuję" means "Thank You" and "Dzięki" means "Thanks".

Pronunciation
I have already added pronunciations of the words/sentences. If you need more of them, please let me know at my commons or polish Wikipedia talk page. Best regards, pl:w:user:odder/commons:user:odder 14:28, 30 September 2006 (UTC)

yo soy

"no" is ordinary word. Mustn't use its in official texts.

Translation
Dear all, I think using "Jak leci?" might be unfortunate. Possibly it would be better to use "Co tam?". It is more natural. Jak leci? - what's up? (lit. how's it flying?) (Yah-k l-eh-chee) About this sound pronunciation (help·info) Co tam? - what's up? (lit. what there?) (Tso tham)

title: Talk:Polish/Some useful expressions


text:
User talk:Thunderbunny~enwikibooks

Welcome, Thunderbunny! Thanks for pitching in with C :) You can get monospaced text on lines beginning with a single space. Have a look how I did it on Programming:C control - keep contributing :) Dysprosia 09:21, 8 Dec 2003 (UTC)

Hi :) Instead of removing the paragraph, could you add some reasons why using short/unsigned keywords is useful?

By the way, do you think mentioning scope later on would be useful? Dysprosia 00:55, 20 Dec 2003 (UTC)

Wikimedia Pennsylvania
Hello there!

I'm writing to inform you that we are now forming the first local Wikimedia Chapter in the United States: Wikimedia Pennsylvania. Our goals are to perform outreach and fundraising activities on behalf of the various Wikimedia projects. If you're interested in being a part of the chapter, or just want to know more, you can: Thanks and I hope you sign up!  Cbrown1023  talk  16:11, 12 July 2007 (UTC)
 * Contact us on IRC at #wikimedia-pa
 * Join our mailing list
 * Visit our blog at http://wmfpa.blogspot.com
 * Sign our list of interested participants

Your account will be renamed
Hello,

The developer team at Wikimedia is making some changes to how accounts work, as part of our on-going efforts to provide new and better tools for our users like cross-wiki notifications. These changes will mean you have the same account name everywhere. This will let us give you new features that will help you edit and discuss better, and allow more flexible user permissions for tools. One of the side-effects of this is that user accounts will now have to be unique across all 900 Wikimedia wikis. See the announcement for more information.

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Renamed
 This account has been renamed as part of single-user login finalisation. If you own this account you can |log in using your previous username and password for more information. If you do not like this account's new name, you can choose your own using this form after logging in: . -- Keegan (WMF) (talk) 05:35, 19 April 2015 (UTC)

title: User talk:Thunderbunny~enwikibooks


text:
User:Paddu

See w:User:Paddu.

As per Wikijunior Solar System/Authors (I haven't contributed to that book), in case my nationality & year of birth are required, they are -- Indian, 1982.

C++ Resources:
 * http://www.research.att.com/~bs/bs_faq.html
 * http://www.research.att.com/~bs/new_learning.pdf (sections 1, 2, 4, 5)
 * http://www.research.att.com/~bs/bs_faq2.html
 * http://www.parashift.com/c++-faq-lite/
 * http://www.nedprod.com/Niall_stuff/MarshallClineConversation.html
 * http://www.cprogramming.com/tutorial.html
 * http://cppreference.com/
 * http://www.icce.rug.nl/documents/cplusplus/

Multibyte Characters:
 * http://www-ccs.ucsd.edu/c/charset.html

Some More Bookmarks:
 * http://cpptips.hyperformix.com/Operators.html
 * http://oss.software.ibm.com/icu/docs/papers/cpp_report/the_assignment_operator_revisited.html
 * http://www.research.att.com/~bs/sibling_rivalry.pdf
 * http://www.research.att.com/~bs/3rd_tour2.pdf
 * http://www.lysator.liu.se/c/
 * http://www.oakroadsystems.com/tech/c-predef.htm
 * http://www.oakroadsystems.com/tech/cppredef.htm

/sandbox

title: User:Paddu


text:
User talk:Siegfried Petry~enwikibooks

Änderungen an dt. Seiten (wichtig!!)
Hallo. Bevor du Seiten weiterhin hier in der englischen Version von Wikibooks änderst, verschiebe/kopiere sie doch bitte in die deutsche Version und mache die Änderungen dann dort. Das bezieht sich vor allem auch auf den Upload von Bildern, da es nur doppelte Arbeit bedeutet sie erst hier hochzuladen und dann nochmal in derdeutschen Version. Alle deutschen Seiten im englischen Wikibooks werden über kurz oder lang gelöscht werden !!! --Moolsan 13:19, 22 Jul 2004 (UTC)

Please use TeX and plain text instead of uploading all these images. Guanaco 18:46, 21 Jun 2004 (UTC)

I have listed all your images on Votes for deletion. They will not be deleted until they are converted to TeX. Before you upload any more images, please read this. Guanaco 21:39, 21 Jun 2004 (UTC)

Do realise that if you upload images, it is impossible for others to edit your formulas unless we reupload the image. With TeX, anyone can edit it. It's not that difficult to learn:
 * $$\int_0^\infty e^{-r^2}\,dr$$

see? Dysprosia 21:43, 21 Jun 2004 (UTC)

 * Please please please stop with the images. Use TeX it is so much better. Every image you upload that contains a formula is going to have to be deleted and converted to TeX :-(  Theresa knott 13:23, 1 Jul 2004 (UTC)

The use of images instead of TeX prevents other users from editing the formulae. Kindly do not revert the changes that I have made - if you do not want to learn TeX and create TeX formulae, then do not revert the changes that others are making to our work. Dysprosia 07:20, 2 Jul 2004 (UTC)

Die Mechanik flüssiger und gasförmiger Körper
Diese Seite haben wir eigentlich mit Absicht nicht auf die Leitseite genommen, da wir uns in der Diskussion über die Leitseite darauf verständigt haben, dass dort nur Artikel stehen sollen, die (fast) fertig sind. Zumindest die alte Leitseite behauptete, das Buch sei nur zu 50% fertig. Da ich nicht beurteilen kann, ob das Buch jetzt tatsächlich inzwischen fertig ist, oder nicht möchte ich dich bitten, im Regal Physik die entsprechende Angabe auf 100% zu ändern, oder das Buch vorerst mal wieder von der Leitseite zu entfernen. (Ich bin nicht böse und das soll auch kein Tadel sein; schließlich müssen wir uns an die neue Leitseite erst mal alle gewöhnen).

Grüßle, --berni 23:04, 14 Jul 2004 (UTC)

Your account will be renamed
Hello,

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Unfortunately, your account clashes with another account also called Siegfried Petry. To make sure that both of you can use all Wikimedia projects in future, we have reserved the name Siegfried Petry~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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title: User talk:Siegfried Petry~enwikibooks


text:
Romanian

Introduction

 * 1) About the language
 * 2) Pronunciation and alphabet
 * 3) Common phrases
 * 4) Flag of Transnistria (state).svgrs and colors
 * 5) Months and days of the week
 * 6) List of words

Lessons

 * 1) Cum mă prezint? — Introducing yourself
 * 2) Gramatică de bază — Basic Grammar
 * 3) Călătorie — Traveling
 * 4) Verbe — Verbs
 * 5) Recreere — Recreation
 * 6) Trecut — Past Tense
 * 7) /Viitor/ —Future Tense
 * 8) Familie — Family
 * 9) Şcoală — School
 * 10) De băut şi de mâncat — Food and Drink
 * 11) Cumpărături — Shopping
 * 12) Casa — The House
 * 13) Corpul — The Body
 * 14) Cultura românească — Romanian Culture

Appendices

 * 1) Appendix C: Typing Romanian Characters
 * 2) Appendix E: Solutions to Exercises
 * 3) Appendix EF: English-Romanian dictionary (alphabetically)
 * 4) Appendix FE: Romanian-English dictionary (alphabetically)
 * 5) Appendix S: Slang
 * 6) Appendix V: Romanian Verb Tenses and Conjugations
 * 7) Appendix W: Romanian Web Resources

Indices

 * 1) Index I: Vocabulary topics
 * 2) Index II: Grammar topics
 * 3) Index III: Pronunciation topics
 * 4) Index IV: Verb tense topics

Enseignement du roumain ルーマニア語 Roemeens Rumuński/Okładka Română Romanian kieli Румунська мова רומנית

title: Romanian


text:
Japanese/Vocabulary/Colors

 * Note that the six basic colors, black, white, red, yellow, brown, and blue are in their noun forms. Adding -い(-i) to the end of these colors will make them adjectives, allowing them to be placed before a noun: 赤い red (adj.), 青い blue (adj.), 黄色い yellow (adj.), 茶色い brown (adj.), 白い white (adj.), 黒い black (adj.).

Verbs
grammar rules:
 * adj → become ～ verb (～になる)
 * ～い → ～む (e.g. 悲しい → 悲しむ, 赤い → 赤む)

 * noun → take on ～ verb (～を帯びる)
 * ～ → ～ばむ (e.g. 汗 → 汗ばむ, 赤 → 赤ばむ)

 * verb → passive verb
 * ～ → (imperfective form of ～)る (e.g. 忘る → 忘れる)

title: Japanese/Vocabulary/Colors


text:
Modern Greek

Welcome to the Modern Greek WikiBook! This book is aimed at teaching from absolute beginners to advanced. It is a work in progress and is currently undergoing major restructuring - please see the discussion page or the restructuring page, please consider helping the project by contributing.

 * Note: This book is for Modern Greek, for Ancient Greek, click here, for Koine (Biblical) Greek, click here.

Lesson 1 - Alphabet and Reading

 * Lesson 1.1: Letters α, ι, κ, ο, τ, and κ
 * Lesson 1.2: Letters ν, μ, ε, and λ
 * Lesson 1.3: Letters π, σ, and δ
 * Lesson 1.4: Letters η, υ, ω, and β
 * Lesson 1.5: Letters φ, ζ, and γ
 * Lesson 1.6: Letters θ, χ, ξ, and ψ
 * Lesson 1.7: Alphabet review

Lesson 2 - Useful Phrases

 * Lesson 2.1: Common phrases
 * Lesson 2.2: Greetings

Lesson 3 - Gender of Nouns and Cases

 * Lesson 3.1: Introduction to Cases
 * Lesson 3.2: Gender of Nouns
 * Lesson 3.3: Pronouns

Lesson 4 - Present Tense Verbs

 * Lesson 4.1: To Be and To Have
 * Lesson 4.2: First Conjugation (Type I)
 * Lesson 4.3: Second Conjugation (Type IIA and IIB)
 * Lesson 4.4: First Conjugation (Passive Only)
 * Lesson 4.5: Second Conjugation (Passive Only)

Lesson 5 - Sample Dialogues

 * Lesson 5.1: Greetings revisited, names and nationalities
 * Lesson 5.2: "Can you repeat that, please?"
 * Lesson 5.3: The question words
 * Lesson 5.4: Getting Directions
 * Lesson 5.5: Notes on sentence structure

Lesson 6 - Numbers, Time and Date

 * Lesson 6.1: 1-10
 * Lesson 6.2: 11-100
 * Lesson 6.3: 100+
 * Lesson 6.4: Time
 * Lesson 6.5: Days/Months

Lesson 7 - Some more grammar

 * Lesson 7.1: Present Tense Irregular Verbs
 * Lesson 7.2: Prepositions
 * Lesson 7.3: Comparative and Superlative
 * Lesson 7.4: "I need" and "I must"
 * Lesson 7.5: "I think" and more adjectives
 * Lesson 7.6: "υπάρχω"

Lesson 8 - Sample Dialogues II

 * Lesson 8.1: Meeting the family
 * Lesson 8.2: Buying something
 * Lesson 8.3: "Where can I find?" and directions
 * Lesson 8.4: Eating and Drinking in Greece
 * Lesson 8.5: Days/Months Part II

Lesson 9 - Past Tense

 * Lesson 9.1: Imperfect (Past Continuous) Tense
 * Lesson 9.2: Simple Past (Aorist) Tense
 * Lesson 9.3: Past Perfect Tense
 * Lesson 9.4: Past είμαι and έχω

Lesson 10 - Future Tense

 * Lesson 10.1: Simple Future
 * Lesson 10.2: Continuous Future
 * Lesson 10.3: Future Perfect

Lesson 11 - More Tenses and Grammar

 * Lesson 11.1: Subjunctive
 * Lesson 11.2: Imperative
 * Lesson 11.3: Passive Verbs

Lesson 12 - Sample Dialogues III

 * Lesson 12.2: My Holidays
 * Lesson 12.2: At the Doctors

Appendix A - Vocabulary Lists

 * Vocabulary 1: Family
 * Vocabulary 2: Professions
 * Vocabulary 3: Food
 * Vocabulary 4: Clothing
 * Vocabulary 5: Body
 * Vocabulary 6: In the house
 * Vocabulary 7: Around Town
 * Vocabulary 8: Colours
 * Vocabulary 9: Weather
 * Vocabulary 10: Countryside

Appendix B - Grammar Summary

 * Grammar Summary 1: List of Tenses
 * Grammar Summary 2: About Nouns
 * Grammar Summary 3: The Prepositions and the Conjuctions
 * Grammar Summary 4: Syntax Notes
 * Grammar Summary 8: Grammar Glossary
 * Grammar Summary 9: Verb Tables

Appendix C - Reading Exercises

 * Reading 01
 * Reading 02
 * Reading 03
 * Reading 04

Credits

 * Credits, legal, and licensing information for materials used from third-party sources

Гръцки език Neugriechisch Griego/Introducción Grec 현대 그리스어 입문 יוונית מודרנית Nieuwgrieks ギリシア語 Grego moderno Greacă Мова людства/Грецька 希腊语 නවීන ග්‍රීක භාෂාව

title: Modern Greek


text:
Talk:Algebra/Functions

Remark by initial writer of this module: Algebra/Functions
''Note: I think the topic of functions deserves a bit of introduction, though I'm not sure if this is the right module for it. Calculus/Functions covers similar ground, but this explanation is intended as less 'technical' and more level-appropriate. Perhaps it's the wrong tone to take in this book, though. Please post thoughts to the talk page. --Spikey 04:12, 10 Dec 2003 (UTC)''

Moving introductory section of "Function graphing" module here
I am thinking of perhaps moving the introductory section of the next module Algebra/Function Graphing to this module, Algebra/Functions, and renaming this module Algebra/Functions and graphing and the next module would be renamed Algebra/Linear function graphing. This is because the existing Algebra/Function Graphing module has become fairly long, it only covers linear function graphing, and problems have not been added yet. Any thoughts on this matter? H Padleckas 14:00, 10 November 2005 (UTC)

To Do List For This Page
1. Extend Creating Functions with graphics like rest of the page. Nfgdayton (talk) 17:46, 23 July 2010 (UTC)

openion
I think the graph of fog is not correct its for gof because in fog  g is a function from first set to secound and f fron secound to outbut, fog from first set to the οutbut

I agree...--Busukxuan (discuss • contribs) 16:09, 5 April 2012 (UTC)

 * You both are correct, I have edited the image so that it is now accurate. Thenub314 (talk) 19:13, 5 April 2012 (UTC)

title: Talk:Algebra/Functions


text:
General Chemistry/Atomic Structure

Atomic Structure

 * 1) History of Atomic Structure [[File:100 percent.svg]]
 * 2) Subatomic Particles [[File:100 percent.svg]]
 * 3) Introduction to Quantum Theory [[Image:75%.svg]]
 * 4) The Quantum Model [[Image:75%.svg]]
 * 5) *The Quantum Atom [[Image:75%.svg]]
 * 6) *Shells and Orbitals [[Image:75%.svg]]
 * 7) *Filling Electron Shells [[Image:75%.svg]]
 * 8) *Periodicity and Electron Configurations [[Image:75%.svg]]
 * 9) Octet Rule and Exceptions [[File:100 percent.svg]]

title: General Chemistry/Atomic Structure


text:
General Chemistry/Atomic Structure/Subatomic Particles

Particle Properties
Before learning about subatomic particles, some basic properties should be understood.

Charge
Particles may be electrically charged. Charge is a property which defines the force that a particle will exert on other charged particles. There is a well known saying that applies perfectly: "Opposites attract." (Likewise, like charges repel.) Positive charges and negative charges will attract each other and come together. Two positive or two negative charges will push each other away.

The amount of charge a particle has is measured in coulombs, but it is more conveniently expressed in terms of an integer. For instance, a helium ion that has 2 less electrons than usual has a charge of +2, and a bromide ion with one more electron than usual has a charge of -1. (This may seem backwards, but remember that an electron has a negative charge.) Notice that charge not only applies to subatomic particles, but also ions and other things as well. Always remember to specify if a charge is positive or negative. Unlike ordinary numbers, we always write the plus sign for positive charges to avoid confusion with a negative charge.

Mass
Mass is the measure of inertia. From a subatomic point of view, mass can also be understood in terms of energy, but that does not concern us when dealing with chemistry. Mass for particles, atoms, and molecules is not measured in grams, as with ordinary substances. Instead, it is measured in atomic mass units, or amu. For more information about mass and amu, read the previous chapters on properties of matter.

The Nucleus

At the center of each atom lies the nucleus. It is incredibly small: if you were to take the average atom (itself miniscule in size) and expand it to the size of a football stadium, then the nucleus would be about the size of a marble. It is, however, astoundingly dense: despite the tiny percentage of the atom's volume it contains nearly all of the atom's mass. The nucleus almost never changes under normal conditions, remaining constant throughout chemical reactions. Nuclei are themselves made up of a pair of smaller and more dense particles, the proton and the neutron. These particles are collectively dubbed nucleons.

Protons
Protons have a charge of +1 and a mass of 1 amu. They are often represented by a $$p$$.

Protons will be important when learning about acids and bases—they are the essence of acid. Remember that the number of protons in an atom is its atomic number, and defines what element it will be. The number of protons in a nucleus ranges from one to over a hundred.

Consider the element hydrogen. Its atomic number is 1, so it has one proton and one electron. If it is made into an ion (an atom with missing or extra electrons), it will simply be a lone proton. Thus, a proton is the nucleus of a hydrogen atom, and a proton is a hydrogen ion. Therefore, a proton can be written as $$\text{H}^+$$ or $$_1^1\text{H}^+$$, both symbols for a hydrogen ion.

Neutrons
Neutrons have no charge and a mass of 1 amu. A neutron is slightly heavier than a proton, but the difference is insignificant. Neutrons are often written $$n$$.

Unlike the protons, neutrons cannot exist outside the nucleus indefinitely as they become unstable and break down. Within one nucleus there can be many protons and neutrons all in close proximity to one another. The number of neutrons in a nucleus ranges from zero to over a hundred.

You may wonder why neutrons exist. They have no charge, so can they do anything? The answer is yes—neutrons are very important. Remember that opposites attract and likes repel. If so, then how can several protons stay clumped together in the dense nucleus of an atom? It would seem as if the protons would repel and scatter the nucleus. However, there is a strong nuclear force that holds the nucleus together. This incredible force causes nucleons to attract each other with much greater strength than the electric force can repel them, but only over extremely short distances.

A delicate balance exists between the number of protons and neutrons. Protons, which are attracted to one another via the strong force but simultaneously repelled by their electromagnetic charges, cannot exist in great numbers within the nucleus without the stabilizing action of neutrons, which are attracted via the strong force but are not charged. Conversely, neutrons lend their inherent instability to the nucleus and too many will destabilize it.

Lastly, neutrons are very important in nuclear reactions, such as those used in power plants. Neutrons act like a bullet that can split an atom's nucleus. Because they have no charge, neutrons are neither attracted nor repelled by atoms and ions.

The Electron Cloud
Surrounding the dense nucleus is a cloud of electrons. Electrons have a charge of -1 and a mass of 0 amu. That does not mean they are massless. Electrons do have mass, but it is so small that it has no effect on the overall mass of an atom. An electron has approximately 1/1800 the mass of a proton or neutron. Electrons are written $$e^-$$.

Electrons orbit the outside of a nucleus, unaffected by the strong nuclear force. They define the chemical properties of an atom because virtually every chemical reaction deals with the interaction or exchange of the outer electrons of atoms and molecules.

Electrons are attracted to the nucleus of an atom because they are negative and the nucleus (being made of protons and neutrons) is positive. Opposites attract. However, electrons don't fall into the nucleus. They orbit around it at specific distances because the electrons have a certain amount of energy. That energy prevents them from getting too close, as they must maintain a specific speed and distance. Changes in the energy levels of electrons cause different phenomena such as spectral lines, the color of substances, and the creation of ions (atoms with missing or extra electrons).

Electron Interactions
Atoms will always have equal numbers of protons and electrons, so their overall charge is zero. Atoms are neutral. Ions, on the other hand, are atoms that have gained or lost electrons and now have an unequal number of protons and electrons. If there are extra electrons, the ion will be negatively charged. If there are missing electrons, the ion will be positively charged, due to the majority of positive protons.

Valence electrons (the outermost electrons) are responsible for an atom's behavior in chemical bonds. The core electrons are all of the electrons not in the outermost shell, and they rarely get involved. An atom will attempt to fill its valence shell. This occurs when an atom has eight valence electrons (as explained in the next chapter), so atoms will undergo chemical bonds to either share, give, or take the electrons it needs. Sodium, for example, is very likely to give up its one valence electron, so that its outer shell is empty (the shell underneath it is full). Chlorine is very likely to take an electron because it has seven and wants eight. When sodium and chlorine are mixed, they exchange electrons and create sodium chloride (table salt). As a result, both elements have full valence shells, and a very stable compound is formed.


text:
General Chemistry/Shells and Orbitals

Electron shells
Each shell is subdivided into subshells, which are made up of orbitals, each of which has electrons with different angular momentum. Each orbital in a subshell has a characteristic shape, and is named by a letter. They are: s, p, d, and f. In a one-electron atom (e.g. H, He+, Li+2, etc.) the energy of each orbital within a particular shell is identical. However, when there are multiple electrons, they interact and split the orbitals into slightly different energies. The letters s, p, d and f specify the subshells (angular quantum number l) and the orbital is specified by the magnetic quantum number m. The angular and magnetic quantum numbers relate to the magnitude and direction of the electron's angular momentum, respectively. Within any particular subshell, the energy of the orbitals depends on the angular momentum of orbitals s, p, d, and f in order of lowest to highest energy.

This image shows the orbitals (along with hybrid orbitals for bonding and a sample electron configuration, explained later).

The s subshell
The simplest subshell in the atom is the 1s subshell. It has no radial or angular nodes: the 1s subshell is simply a sphere of electron density. A node is a point where the electron positional probability is zero. As with all subshell the number of radial nodes increases with the principle quantum number (i.e. the 2s orbital has one radial node, the 3s has two etc.). Because the angular momentum quantum number is 0, there is only one choice for the magnetic quantum number - there is only one s orbital per shell. The s orbital can hold two electrons, as long as they have different spin quantum numbers. S orbitals are involved in bonding.

$$\begin{matrix} n &=& 1, 2, 3, ... \\ l &=& 0 \\ m_l &=& 0 \\ m_s &=& +\frac{1}{2}, -\frac{1}{2} \\ \end{matrix}$$

The p subshell
Starting from the 2nd shell, there is a set of p subshell. The angular momentum quantum number of the electrons confined to p subshell is 1, so each orbital has one angular node. There are 3 choices for the magnetic quantum number, which indicates 3 differently oriented p subshell. Finally, each orbital can accommodate two electrons (with opposite spins), giving the p orbitals a total capacity of 6 electrons.

$$\begin{matrix} n &=& 2, 3, 4, ... \\ l &=& 1 \\ m_l &=& -1,0,1 \\ m_s &=& +\frac{1}{2}, -\frac{1}{2} \\ \end{matrix}$$

The orbital of p subshell all have two lobes of electron density pointing along each of the axes. Each one is symmetrical along its axis. The notation for the orbitals of p subshell indicate which axis it points down, i.e. px points along the x axis, py on the y axis and pz up and down the z axis. Note that although pz corresponds to the ml = 0 orbital, px and py are actually mixtures of ml = -1 and ml = 1 orbitals. The p orbitals are degenerate — they all have the same energy. P orbitals are very often involved in bonding.

The d subshell
The first set of d orbitals is the 3d set. The angular momentum quantum number is 2, so each orbital has two angular nodes. There are 5 choices for the magnetic quantum number, which gives rise to 5 different d orbitals. Each orbital can hold two electrons (with opposite spins), giving the d orbitals a total capacity of 10 electrons.

$$\begin{matrix} n &=& 3, 4, 5, ... \\ l &=& 2 \\ m_l &=& -2,-1,0,1,2 \\ m_s &=& +\frac{1}{2}, -\frac{1}{2} \\ \end{matrix}$$

Note that all the d orbitals have four lobes of electron density, except for the dz2 orbital, which has two opposing lobes and a doughnut of electron density around the middle. The d orbitals can be further subdivided into two smaller sets. The dx2-y2 and dz2 all point directly along the x, y, and z axes. They form an eg set. On the other hand, the lobes of the dxy, dxz and dyz all line up in the quadrants, with no electron density on the axes. These three orbitals form the t2g set. In most cases, the d orbitals are degenerate, but sometimes they can split, with the eg and t2g subsets having different energy. Crystal Field Theory predicts and accounts for this. D orbitals are sometimes involved in bonding, especially in inorganic chemistry.

The f subshell
The first set of f orbitals is the 4f subshell. There are 7 possible magnetic quantum numbers, so there are 7 f orbitals. Their shapes are fairly complicated, and they rarely come up when studying chemistry. There are 14 f electrons because each orbital can hold two electrons (with opposite spins).

$$\begin{matrix} n &=& 4, 5, 6, ... \\ l &=& 3 \\ m_l &=& -3,-2,-1,0,1,2,3 \\ m_s &=& +\frac{1}{2}, -\frac{1}{2} \\ \end{matrix}$$

title: General Chemistry/Shells and Orbitals


text:
General Chemistry/Filling Electron Shells

Filling Electron Shells
When an atom or ion receives electrons into its orbitals, the orbitals and shells fill up in a particular manner.

Aufbau principle
You may consider an atom as being "built up" from a naked nucleus by gradually adding to it one electron after another, until all the electrons it will hold have been added. Much as one fills up a container with liquid from the bottom up, the orbitals of an atom are filled from the lowest energy orbitals to the highest energy orbitals.

Orbitals with the lowest principal quantum number ($$n$$) have the lowest energy and will fill up first, in smaller atoms. Larger atoms with more subshells will seem to fill "out of order", as the other factors influencing orbital energy become important. Within a shell, there may be several orbitals with the same principal quantum number. In that case, more specific rules must be applied. For example, the three p orbitals of a given shell all occur at the same energy level. So, how are they filled up? Answer: all the three p orbitals have same energy so while filling the p orbitals we can fill any one of the Px, Py or Pz first. It is a convention that we chose to fill Px first, then Py and then Pz for our simplicity. Hence you can opt for filling these three orbitals from right to left also. Aufbau principle state that “atomic orbitals are filled with electrons in order of increasing energy level”.

Hund's Rule
According to Hund's rule, orbitals of the same energy are each filled with one electron before filling any with a second. Also, these first electrons have the same spin.

This rule is sometimes called the "bus seating rule". As people load onto a bus, each person takes his or her own seat, sitting alone. Only after all the seats have been filled will people start doubling up.

Pauli Exclusion principle
No two electrons can have all four quantum numbers the same. What this translates to in terms of our picture of orbitals is that each orbital can only hold two electrons, one "spin up" (+½) and one "spin down" (-½).

Orbital Order
1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p, 6s, 4f, 5d, 6p, 7s, 5f, 6d, 7p, 8s.

Although this looks confusing, there is an easy way to remember. Go in order of the lines from top to bottom, top right end to bottom left of each line.

Understanding the above rules and diagrams will allow you to determine the electron configuration of almost any atom or ion.

How to Write the Electron Configuration of an Isolated Atom
Electron-configuration notation is relatively straightforward. An isolated Calcium atom 20Ca, for example, would have configuration of 1s22s22p63s23p64s2 in its ground state. Other configurations like 1s22s22p63s23p64s14p1 are possible, but these excited states have a higher energy. They are not stable and generally only exist for a brief moment.

The ground state configuration for Ca could be abbreviated by using the preceding noble gas (the elements found all the way on the right of the periodic table) as [Ar]4s2, where Ar is argon.

Noble gases have very stable configurations, and are extremely reluctant to lose or gain electrons. Noble gas atoms are also the only ones regularly found as isolated atoms in the ground state. Atoms of other elements all undergo bonding under the conditions that we live under and this affects the orbitals that the outermost electrons are in. In that sense the electron configurations for the other elements are somewhat hypothetical: to encounter an isolated atom of, say, tungsten (W), we would have to first vaporize a metal that boils at 5800K. However, knowing atomic configurations is useful because it does help us to understand how and why they bond, i.e. why and how they change the configuration of their outer valence electrons.

Rule of Stability
A subshell is particularly stable if it is half full or full. Given two configurations, the atom would "choose" the more stable one.

Example: In the following configuration, Cu: [Ar]4s23d9, copper's d shell is just one away from stability, and therefore, one electron from the s shell jumps into the d shell: [Ar]4s13d10. This way, the d shell is full, and is therefore stable, and the s shell is half full, and is also stable.

Another example: Chromium has a configuration of [Ar]4s13d5, although you would expect to see four d electrons instead of five. This is because an s electron has jumped into the d orbital, giving the atom two half-full shells—much more stable than a d orbital with only four electrons.

The stability rule applies to atoms in the same group as chromium and copper.

If one of these atoms has been ionized, that is, it loses an electron, it will come from the s orbital rather than the d orbital. For instance, the configuration of Cu+ is [Ar]4s03d10. If more electrons are removed, they will come from the d orbital.

Magnetism

Magnetism is a well-known effect. Chances are, you have magnets on your refrigerator. As you already know, only certain elements are magnetic. Electron configurations help to explain why.

Diamagnetism is actually a very weak repulsion to magnetic fields. All elements have diamagnetism to some degree. It occurs when there are paired electrons.

Paramagnetism is an attraction to external magnetic fields. It is also very weak. It occurs whenever there is an unpaired electron in an orbital.

Both diamagnetism and paramagnetism are responses of spins acting independently from each other. This leads to rather weak repulsion and attraction respectively. However, when they are located in a solid they may also interact with each other and respond collectively and that can lead to rather different properties:

Ferromagnetism is the permanent magnetism that we encounter in our daily lives. It occurs when all the unpaired spins in a solid couple and tend to align themselves in the same direction, leading to a strong attraction when exposed to a magnetic field. This only occurs at room temperature with three elements: iron (Fe), nickel (Ni), and cobalt (Co). Gadolinium (Gd) is a borderline case. It loses its ferromagnetism at 20oC; above that temperature the spins start to act alone. However, there are many alloys and compounds that exhibit strong ferromagnetic coupling. The strongest one is Nd2Fe14B

Antiferromagnetism is also a permanent magnetism in which unpaired spins align, but they do so in opposite directions. The result that the material does not react very strongly to a magnetic field at all. Chromium (Cr) is an example.

'Ferrimagnetism is a combination of ferro- and antiferromagetism. Unpaired spins align partly in opposite directions, but the compensation is not complete. This is why the material is still attracted strongly to a magnetic field. Magnetite Fe3O4 is such a substance. It was the first material studied for its magnetic properties and may, well, be the one sitting on your fridge.


text:
General Chemistry/Octet Rule and Exceptions

The octet rule refers to the tendency of atoms to prefer to have eight electrons in the valence shell (outer orbital). When atoms have fewer than eight electrons, they tend to react and form more stable compounds. When discussing the octet rule, we do not consider d or f electrons. Only the s and p electrons are involved in the octet rule, making it useful for the representative elements (elements not in the transition metal or inner-transition metal blocks). An octet corresponds to an electron configuration ending with s2p6.

Stability
Atoms will react to get in the most stable state possible. A complete octet is very stable because all orbitals will be full. Atoms with greater stability have less energy, so a reaction that increases the stability of the atoms will release energy in the form of heat or light. Reactions that decrease stability must absorb energy, getting hotter.

The other tendency of atoms is to maintain a neutral charge. Only the noble gases (the elements on the right-most column of the periodic table) have zero charge with filled valence octets. All of the other elements have a charge when they have eight electrons all to themselves. The result of these two guiding principles is the explanation for much of the reactivity and bonding that is observed within atoms: atoms seek to share electrons in a way that minimizes charge while fulfilling an octet in the valence shell.

Example
The formula for table salt is NaCl. It is the result of Na+ ions and Cl- ions bonding together. If sodium metal and chlorine gas mix under the right conditions, they will form salt. The sodium loses an electron, and the chlorine gains that electron. In the process, a great amount of light and heat is released. The resulting salt is mostly unreactive — it is stable. It won't undergo any explosive reactions, unlike the sodium and chlorine that it is made of.

Why? Referring to the octet rule, atoms attempt to get a noble gas electron configuration, which is eight valence electrons. Sodium has one valence electron, so giving it up would result in the same electron configuration as neon. Chlorine has seven valence electrons, so if it takes one it will have eight (an octet). Chlorine has the electron configuration of argon when it gains an electron.

The octet rule could have been satisfied if chlorine gave up all seven of its valence electrons and sodium took them. In that case, both would have the electron configurations of noble gasses, with a full valence shell. However, their charges would be much higher. It would be Na7- and Cl7+, which is much less stable than Na+ and Cl-. Atoms are more stable when they have no charge, or a small charge.

Exceptions
There are few exceptions to the octet rule.

Two Electrons
The main exception to the rule is hydrogen, which is at its lowest energy when it has two electrons in its valence shell. Helium (He) is similar in that it, too, only has room for two electrons in its only valence shell.

Hydrogen and helium have only one electron shell. The first shell has only one s orbital and no p orbital, so it holds only two electrons. Therefore, these elements are most stable when they have two electrons. You will occasionally see hydrogen with no electrons, but H+ is much less stable than hydrogen with one or two electrons.

Lithium, with three protons and electrons, is most stable when it gives up an electron.

Less Than an Octet
Other notable exceptions are aluminum and boron, which can function well with six valence electrons. Consider BF3. The boron shares its three electrons with three fluorine atoms. The fluorine atoms follow the octet rule, but boron has only six electrons. Although atoms with less than an octet may be stable, they will usually attempt to form a fourth bond to get eight electrons. BF3 is stable, but it will form BF4- when possible. Most elements to the left of the carbon group have so few valence electrons that they are in the same situation as boron: they are electron deficient. Electron deficient elements often show metallic rather than covalent bonding.

More Than an Octet
In Period 3, the elements on the right side of the periodic table have empty d orbitals. The d orbitals may accept electrons, allowing elements like sulfur, chlorine, silicon and phosphorus to have more than an octet. Compounds such as PCl5 and SF6 can form. These compounds have 10 and 12 electrons around their central atoms, respectively.

Even palladium has 18 electrons in its valence shell

Odd Numbers
Some elements, notably nitrogen, have an odd number of electrons and will form somewhat stable compounds. Nitric oxide has the formula NO. No matter how electrons are shared between the nitrogen and oxygen atoms, there is no way for nitrogen to have an octet. It will have seven electrons instead. A molecule with an unpaired electron is called a free radical and radicals are highly reactive, so reactive that many of them only exist for a fraction of a second. As radicals go, NO and NO2 are actually remarkably stable. At low temperatures NO2 does react with itself to form N2O4, its dimer, that is not a radical.


text:
User:Spikey~enwikibooks

I had an idea over a year ago and posted it to Usenet. That thread pointed me to Wikipedia, which I immediately hailed as the answer to my dreams. By the next day I had forgotten about it.

Later on, though, I found my way back, time and again, and finally actually registered. Wikipedia, however, was not exactly what I was looking for. Wikibooks is.

I'll probably spend the most time in the Mathematics section. That and computer science are my fortés. I've always wanted to use the word forté. I think I've used it wrong.

Stuff I've had a lot to do with

 * Algebra:Functions

title: User:Spikey~enwikibooks


text:
Puzzles/Decision puzzles/Yet Another Weighing/Solution

Puzzles|Decision puzzles|Yet Another Weighing|Solution

One way to solve this would be to try to manually work out all the possible combinations and their sums. That would take a while.

Instead, notice that each item is half the weight of the previous item. Lets assume you have less items and work out the general rule for any number of items, where each is twice as much as the next item:

Items Weights            Number of Combinations 1     5                   1: 5 2      5, 10               3: 5, 10, 15 3      5, 10, 20           7: 5, 10, 15, 20, 25, 30, 35 4      5, 10, 20, 40      15: 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75 5      5, 10, 20, 40, 80

Without even listing them, we can see the pattern. The numbers 1, 3, 7, 15 follow the formula of 2n - 1, where n=1, 2, 3, 4 i.e. the number of items.

For 5 items, n=5, 25 - 1 = 31.

The pattern would continue for more items: 6 - 63 7 - 127 8 - 255 ...


text:
User talk:Spikey~enwikibooks

Welcome Spikey ! I feel ya on what you said in your usenet post. I hope for the exact same thing (interactive, free, good textbooks, although my primary interest is in science rather than math).

--Karl Wick

HSE
Would you contribute to High School Extensions? r3m0t 20:31, 11 Dec 2003 (UTC)

Oh, you're welcome. -- Emperorbma 04:36, 18 Dec 2003 (UTC)

Your account will be renamed
Hello,

The developer team at Wikimedia is making some changes to how accounts work, as part of our on-going efforts to provide new and better tools for our users like cross-wiki notifications. These changes will mean you have the same account name everywhere. This will let us give you new features that will help you edit and discuss better, and allow more flexible user permissions for tools. One of the side-effects of this is that user accounts will now have to be unique across all 900 Wikimedia wikis. See the announcement for more information.

Unfortunately, your account clashes with another account also called Spikey. To make sure that both of you can use all Wikimedia projects in future, we have reserved the name Spikey~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.

Your account will still work as before, and you will be credited for all your edits made so far, but you will have to use the new account name when you log in.

Sorry for the inconvenience.

Yours, Keegan Peterzell Community Liaison, Wikimedia Foundation 23:43, 17 March 2015 (UTC)

Renamed
 This account has been renamed as part of single-user login finalisation. If you own this account you can |log in using your previous username and password for more information. If you do not like this account's new name, you can choose your own using this form after logging in: . -- Keegan (WMF) (talk) 05:32, 19 April 2015 (UTC)

title: User talk:Spikey~enwikibooks


text:
C Programming/Preliminaries

Before learning C syntax and programming constructs, it is important to learn the meaning of a few key terms that are central in understanding C.

Block Structure, Statements, Whitespace, and Scope
Next we'll discuss the basic structure of a C program. If you're familiar with PASCAL, you may have heard it referred to as a block-structured language. C does not have complete block structure (and you'll find out why when you go over functions in detail) but it is still very important to understand what blocks are and how to use them.

So what is in a block? Generally, a block consists of executable statements.

But before we delve into blocks, let's examine statements. One way to describe statements is they are the text (and surrounding whitespace) the compiler will attempt to turn into executable instructions. A simpler definition is statements are bits of code that do things. For example:

This declares an integer variable, which can be accessed with the identifier 'i', and initializes it to the value 6. The various data types are introduced in the chapter Variables.

You might have noticed the semicolon at the end of the statement. Statements in C always end with a semicolon. Leaving off the semicolon is a common mistake many people make, beginners and experts alike! So until it becomes second nature, be sure to double check your statements!

Since C is a "free-format" language, several statements can share a single line in the source file, like this:

There are several kinds of statements. You've already seen some of them, such as the assignment. A substantial portion of this book deals with statement construction.

Back to our discussion of blocks. In C, blocks begin with an opening brace "{" and end with a closing brace "}". Blocks can contain other blocks which can contain their own blocks, and so on.

Let's look at a block example.

You can use blocks with the preceding statements, such as the main function declaration (and other statements we've not yet covered), but you can also use blocks by themselves.

Whitespace refers to the tab, space and newline characters that separate the text characters that make up the source code. Like many things in life, it's hard to appreciate whitespace until it's gone. To a C compiler, the source code

is the same as

which is also the same as

The compiler simply ignores most whitespace (except, for example, when it separates  from  ). However, it is common practice to use spaces (or tabs) to organize source code for human readability.

Most of the time we do not want other functions or other programmer's routines accessing data we are currently manipulating, which is why it is important to understand the concept of scope.

Scope describes the level at which a piece of data or a function is visible. There are two types of scope in C, local and global. When we speak of global scope, we're referring to something that can be seen or manipulated from anywhere in the program. Local scope applies to a program element that can be seen or manipulated only within the block in which it was declared.

Let's look at some examples to get a better idea of scope.

That shows an example of local and global. But what about different scopes inside of functions? (you'll learn more about functions later, for now, just focus on the "main" part.)

Basics of Using Functions
Functions are a big part of programming. A function is a special kind of block that performs a well-defined task. If a function is well-designed, it can enable a programmer to perform a task without knowing anything about how the function works. The act of requesting a function to perform its task is called a function call. Many functions require a function call to hand it certain pieces of data needed to perform its task; these are called arguments. Many functions also return a value to the function call when they're finished; this is called a return value (the return value in the above program is 0).

The things you need to know before calling a function are:
 * What the function does
 * The data type (discussed later) of the arguments and what they mean
 * The data type of the return value and what it means

Many functions use the return value for the result of a computation. Some functions use the return value to indicate whether they successfully completed their work. As you have seen in the intro exercise, the  function uses a return value to provide an exit status to the operating system.

All code other than global data definitions and declarations needs to be a part of a function.

Usually, you're free to call a function whenever you wish to. The only restriction is that every executable program needs to have one, and only one, main function, which is where the program begins executing.

We will discuss functions in more detail in a later chapter, C Programming/Procedures and functions.

The Standard Library
In 1983, when C was in the process of becoming standardized, the American National Standards Institute (ANSI) formed a committee to establish a standard specification of C known as "ANSI C". That standard specification created a basic set of functions common to each implementation of C, which is referred to as the Standard Library. The Standard Library provides functions for tasks such as input/output, string manipulation, mathematics, files, and memory allocation. The Standard Library does not provide functions that are dependent on specific hardware or operating systems, like graphics, sound, or networking. In the "Hello, World" program, a Standard Library function is used which outputs lines of text to the standard output stream.

C/Podstawy

title: C Programming/Preliminaries


text:
Japanese/Grammar/Transitivity

Many Japanese verbs belong to pairs of transitive and intransitive verbs. In Japanese these are known as 他動詞 (other move verb) and 自動詞 (self move verb). Formally, the difference between these is that a transitive verb can take on a direct object, whereas an intransitive verb (normally) cannot. There are a few pairs of distinct verbs in English that correlate to this: "raise"/"rise", "fell"/"fall" and "lay"/"lie".

Transitive verbs can be thought of as causative, requiring an agent to perform an action. Intransitive verbs move on their own and can be thought of as just existing.

This is best explained by example. Contrast the following pairs of sentences:

The general patterns for transitive and intransitive sentences is: The topics of intransitive verbs are usually inanimate.

Some pairings are listed in the following table:

The rule of thumb is that intransitive verbs usually take nouns with the particles 「が」(ga) or 「は」(wa) that act as subjects, whereas transitive verbs take object nouns marked with 「を」(o). Transitive verbs can also take a ga-subject or wa-subject, although it may be omitted. Note that some intransitive verbs can take an o-object that indicates a location. For example, 出る ("to leave") can be used with a direct object that is a location from which the subject is to leave from. See the table below for more examples:

title: Japanese/Grammar/Transitivity


text:
Cell Biology/Energy supply/Glycolysis

Glycolysis, literally meaning "to split sugar," is the initial step in any respiratory system. Glycolysis involves the breaking down of a sugar (generally glucose, although fructose and other sugars may be used) into more manageable compounds in order to produce energy. The net end products of glycolysis are two Pyruvate, two NADH, and two ATP (A special note on the "two" ATP later).

Glycolysis is a process that all organisms undergo; and therefore the most fundamental and primitive of all energy production systems.

Simplified Explanation
Glycolysis is a series of steps cells go through to transform sugar into energy that the cell can use. All cells are equipped to perform glycolysis, as it is the primary method cells make energy. The byproducts of glycolysis may be further digested to release more energy. glycosis occurs in the cytoplasm of a cell in a plant. glycosis is the first stage in Respiration.

Energy Investment Phase
Glycolysis occurs in the cytoplasm of a cell after glucose is ingested through the process of phagocytosis, or "cell eating," in which the cell engulfs a solid compound. Once the glucose is inside the cytoplasm, one molecule of ATP splits and transfers a phosphate group to the glucose, or "phosphorylates" it, so that it becomes an ion which cannot leave the cell because the cell membrane is impermeable to ions. This step effectively allows cells to efficiently absorb and utilize glucose and keep any glucose molecules from escaping. The process of phosphorylation also makes the glucose chemically reactive.

Once the glucose has been phosphorylated, it is called "Glucose-6-Phosphate," which will be abbreviated G6P. The G6P is rearranged into Fructose-6-Phosphate (F6P) by a protein. When the F6P is created, another ATP molecule splits and the F6P is phosphorylated by another phosphate group. This phosphate is attached to an opposite end of the F6P molecule which is now called Fructose-1, 6-Biphosphate. This is done so that the molecule will be not only more chemically reactive but so that it will split due to the tensions placed upon the molecule by the two phosphate groups. (Phosphate groups have a negative charge; this allows them to be added to create incredibly useful energy compounds, ATP among them. Because like charges repel each other, the two phosphate groups are placed in positions that allow the glucose molecule to split roughly in half, although an enzyme called aldolase is still used to perform the division.)

The Fructose-1, 6-Biphosphate, aided by aldolase, is split into Dihydroxyacetone Phosphate (DP) and Glyceraldehyde-3-Phosphate (G3P), which are isomers of one another. The enzyme isomerase converts these molecules into one another. Because only G3P is used in the final stages of glycolysis, however, the reaction favors the conversion of DP into G3P. The overall effect of this reaction and the following steps is to send two molecules of G3P into the Energy Payoff phase of glycolysis.

Energy Payoff Phase
The G3P molecules then attach to an enzyme that removes two electrons from each G3P, therefore "oxidizing" the molecules. (Please note that the two G3P molecules do not attach to the enzyme at the same time; rather, two of the same enzyme would be used to carry out this reaction.) One electron from each G3P molecule is transferred to a hydrogen ion (H+; a hydrogen ion is also a proton) and one electron from each G3P molecule is transferred to NAD+, a cellular cofactor whose purpose is to carry electrons. The addition of electrons to the H+ and NAD+ combines the two into NADH. Because there are two G3P molecules, there are 2 NADH produced in this step. Since energy is released from the G3P molecules to allow the for the synthesis of the two NADH, some of the remaining energy attaches an inorganic phosphate group in the cell to each G3P molecule, forming 1, 3 Biphosphoglycerate (1,3B).

The two chemically reactive 1,3B molecules now lose the phosphate group that was just attached to them to an ADP, or Adenosine Diphosphate, molecule. The phosphorylation of ADP creates an ATP molecule; because there are two 1,3B molecules, two ATP are created. With this step, the initial ATP investment is repaid, and the 1,3B molecules become 3-Phosphoglycerate, or 3P. After this step is completed, another enzyme relocates the phosphate group on the 3P, changing the 3P into 2-Phosphoglycerate, or 2P.

After the 2P is created, an enzyme called enolase "hydrolyzes" the 2P molecules, which means that one water molecule is removed from each 2P molecule, which means that 2 H2O have been produced because there are two 2P molecules. In this particular case, the 2P is hydrolyzed so that the resulting Phosphoenolpyruvate (PEP) is very unstable and reactive.

The final step of glycolysis involves a protein called BS. Upon attaching to the Pyruvate Kinase proteins, the two PEP are divided into two Pyruvate and two additional phosphate group which are used to phosphorylate two ADP molecules into two ATP molecules.

In prokaryotes, this all but concludes the respiration sequence. There is one final process that is undergone, however; fermentation. The process of glycolysis coupled with the process of fermentation is known as anaerobic respiration, "anaerobic" literally meaning "without air." There are two main types of prokaryotic fermentation: alcohol fermentation and lactate fermentation.

Fermentation
In alcohol fermentation, the two pyruvate molecules lose two oxygen molecules and one carbon molecule are separated from the pyruvate and merge to become CO2 (Carbon Dioxide). The remaining molecule is called Acetaldehyde. The Acetaldehyde is "reduced" (or, gains electrons) by an NADH molecule. Because it is reduced, it increases in size. In this case, the NADH loses two electrons and two hydrogen ions, or protons, which returns it to its original NAD+ status. The two electrons and protons are then transferred to the Acetaldehyde, and it changes into Ethanol. Ethanol is the "alcoholic" ingredient in alcoholic beverages- in other words, a waste product of bacteria is one of the principal ingredients of beer, wine, and other drinks.

In lactate fermentation, no carbon dioxide is released and the pyruvate is instead reduced by the oxidation of NADH into lactate. In more quantitative terms, two protons and two electrons are removed from two NADH and are instead attached to two pyruvate molecules to create two lactate molecules. This lactate is also known as lactic acid, which happens to cause muscle pain and fatigue in animals.

One might wonder why the NADH would be reverted to its original NAD+ status, since energy was used to create it in the first place. The NADH is actually oxidized into NAD+ so that a "glycolytic cycle" can be preserved: if the NAD+ had not been replenished, the prokaryote would eventually run out of organic materials, and it would no longer synthesize ATP, which would mean its eventual death.

In eukaryotes, glycolysis is only the beginning of respiration. Instead of undergoing fermentation, he products of glycolysis are sent into the Krebs Cycle, explained in the next section.

title: Cell Biology/Energy supply/Glycolysis


text:
User:Sabbut

w:es:Usuario:Sabbut

Hi everyone! I'm a college student from Spain, and I know English, French and am trying to learn Japanese ^_^ I'll take a look here every now and then and make a few edits, but I'm usually in the Spanish Wikipedia.

title: User:Sabbut


text: Danish/Cover

title: Danish/Cover


text:
Discrete Mathematics/Selected problems

The problems in the texts you have seen are for you to ensure that you understand the concepts and ideas explored. They are not intended to be very difficult, but understandably they are not very challenging.

Questions here are intended for you to further use the ideas you have learnt to answer some more difficult questions. Some questions are relatively straightforward, some of these questions depend on different sections of this discrete mathematics text, some of these questions are meant to be examination-style questions.

Do not be discouraged by the increase in difficulty - hints are sometimes available, and you will be able to increase your problem solving skills!

Set theory questions
These questions depend on your knowledge of ../Set theory/.

 * 1) We have the sets A={0, 1, 3, 4, 5, 7}, B = {2, 4, 5, 8, 9}, C = {1, 4, 9, 11, 21}. Write the elements of the set $$(A\cap C)\cup B$$   Check your solution:
 * 2) Using the set identities, simplify $$(A\cap B)'\cup A$$
 * 3) (Hint provided) Prove the set $$\{x | x/2 \in \mathbb{N} \}$$ is not a subset of $$\{y | y/4 \in \mathbb{N}\}$$
 * 4) (Hint provided) Prove the set $$\{3n+5| n \in \mathbb{N}\}$$ is not a subset of $$\{6k+6| k \in \mathbb{N}\}$$

title: Discrete Mathematics/Selected problems


text:
Atlas Shrugged

This annotated text both summarizes and analyzes Ayn Rand's epic novel, Atlas Shrugged. In addition, the Appendix singles out the significance of certain Characters, Companies, Concepts, Places, Technologies, and other things in the novel.

Analyses and summaries
All quotes are taken from Ayn Rand. Atlas Shrugged (New York: Penguin 1992.).

The author of this book is Ayn Rand. Other works by Ayn Rand include The Fountainhead, Anthem and We the Living.

Components

 * /Characters/
 * /Companies/
 * /Concepts/
 * /Places/
 * /Technology/
 * /Things/

title: Atlas Shrugged