text:
Puzzles/Action sequences/Crossing the River II/Solution

Puzzles | Action sequences | Crossing the River II | Solution

Label the fathers A, B and C, the sons a, b and c, river. and boat < >.

AaBbCc < >.....         ........ A B Cc  ..<ab>.. ........ A B Cc .....<  >  a b         ........ A B Cc  ..<b >.. a        ........ A BbCc <  >..... a        ........ A B C   ..<bc>.. a        ........ A B C  .....<  >  a b c         ........ A B C   ..<c >.. a b        ........ A B Cc <  >..... a b        ........     Cc  ..<AB>.. a b        ........ Cc .....<  > AaBb ........    Cc  ..<Bb>.. Aa        ........   BbCc <  >..... Aa        ........    b c  ..<BC>.. Aa        ........ b c .....<  > AaB C         ........    b c  ..<a >.. A B C        ........  a b c <  >..... A B C        ........      c  ..<ab>.. A B C        ........ c ....<  >  AaBbC ........     c  ..<C >.. AaBb ........    Cc <  >..... AaBb ........        ...<Cc>. AaBb ........        .....<  > AaBbCc


text:
Puzzles/Medium Sequence 1/Solution

The sequence is an = A(n,n), starting at a0. (A is of course the Ackermann function.)

So the next number in the sequence is $$2^{2^{2^{65536}}}-3$$.

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

title: Puzzles/Medium Sequence 1/Solution


text:
Puzzles/Geometric Puzzles/Matchsticks

Puzzles | Geometric puzzles | Matchsticks

You have 6 unit length matchsticks, and you urgently need to make 4 triangles with unit length sides. You can't use anything except matchsticks to make the triangles, and the matchsticks are indestructable and non-replicable. How do you solve the dilemma?

Solution

title: Puzzles/Geometric Puzzles/Matchsticks


text:
Puzzles/Geometric Puzzles/Matchsticks/Solution

Arrange the six matchsticks along the edges of a tetrahedron, or triangular pyramid. The matchsticks will form 4 triangular faces.


text:
Talk:Abstract Algebra/Group Theory

Linking to other pages
--Fishpi (talk) 09:26, 18 July 2010 (UTC)
 * Are people happy with the fact that this page is just a page of links to other pages?
 * It doesn't seem very book-like to me.
 * It seems that the amount of content we have here would easily fit on one page at the moment, and
 * if it doesn't perhaps it could be broken down into larger conceptual topics rather than individual theorems. If other people agree with this, I don't mind doing the work to restructure it myself.

 * Hi, Fishpi. Seeing others working on the same book is always nice.

 * Issue 1: Should the index for theorems for groups be entirely on this page
 * I seem to agree with you that some of the links should be moved to the page "Abstract Algebra".
 * The theorems seems too small to be moved to "Abstract Algebra"
 * I feel moving links to whole sections like ["Group" and its theorem (cancellations...)], ["Subgroup" and its theorems] to "Abstract Algebra" might be a good idea.

 * Issue 2: one theorem, one page?
 * For me, I think this book need not to be like a book in print and hope that smaller sections can encourage readers to read the whole book
 * Using more pages online would not waste real paper. Unlike real paper books, we can use more pages.
 * I feel learning step by step on many pages is less terrifying than to learn everything on a single page
 * Beginners like me might ~ scream in terror ~ If they see a Big page (like the Older Version).
 * New contents will all cram into a single page when this page grows, if no one try to subdivide it at the beginning. In a moment, people will again see a Big page (I have confidence that many people will work on this book).

 * Is that good for our readers?

--Arydye001 (talk) 15:12, 18 July 2010 (UTC)

 * I'd say the most important thing is that we have good content, so I don't mean to be dictatorial about how it is laid out. I'm new to the Wikibooks project myself, and I've been trying to get used to how things are done round here. My main interest in Wikibooks is in producing books that can be read on an e-book reader or similar, so I tend to favour a structure with fewer links.

 * I see your point about people being scared by a page with lots of theorems on it, but there is one advantage to laying things out on one page, which is that the reader can easily skip backwards and forwards as they read down the page (if results of earlier theorems are used in proving later theorems).

 * I say we focus on producing good quality content at the moment and don't worry about changing the structure, but I'd be interested to hear what other people have to say. Fishpi (talk) 17:36, 18 July 2010 (UTC)

 * I agree that many pages means a lot of distracting flipping or clicking even if the pages are cross-linked.
 * Too few pages means a lot of scrolling and less selectivity in reading.
 * the book should find a balance on amount of content on a page.Arydye001 (talk) 17:51, 18 July 2010 (UTC)

=Lengthy Proofs=
 * Can lengthy proofs show the idea behind them? Arydye001 (talk) 14:54, 25 July 2010 (UTC)

title: Talk:Abstract Algebra/Group Theory


text:
Talk:Puzzles/Logic puzzles/Lying about your Age/Solution

That's correct, Cyp, congratulations! Would you like to write up how you got the solution? Thomas

Done. Cyp 17:56, 18 Oct 2003 (UTC)


text:
Talk:Puzzles/Decision puzzles/12 Coins/Solution

Wow, this is excellent, Cyp! Thomas

 * Thanks. I've actually solved it once before, (maybe a few years ago), so it didn't take too long. (Saw on another forum.) Cyp

What if you lift the requirement to determine whether the coin is heavier or lighter? I can solve the pullzle with 13 coins then, but no more. Funny, especially considering that number of possible outcomes drops from 24 to 12 (with 12 coins). --194.190.194.74 (talk) 08:35, 28 June 2010 (UTC)


text:
Talk:Puzzles/Arithmetical puzzles/Two 4s Equal 64?/Solution

Nice job, Cyp Thomas


text:
Talk:Puzzles/Logic puzzles/Hats/Solution

yep, that's right, Cyp! Thomas

>> Perhaps I'm missing something, but are we assuming that the man in the front is correct in his saying he's wearing a red hat? He could be wrong. What if he's wearing a blue hat? Then the second man would be wearing red, and the third man any color. --Oncogene 12:21, 30 Jun 2005 (UTC)

I think the posted solution was too complicated. I replaced it with one I think is more transparent. Please correct me if I'm wrong. Dusik 21:39, 17 August 2005 (UTC)

More confusing
last man sees either 2 Reds or 1R+1B in both the cases he is not sure about its hats colour So he says dont know man position       red         blue    case 3                   2           0        1 3                    1           1        2 case 1: second must see blue and confuse about its color case 2: second must see red and confuse about its color

so how can first man determine its color??


text:
Puzzles/Logic puzzles/Three Knights

Puzzles | Logic puzzles | Three Knights

A man was sentenced to death, but the king wanted to give him a last chance. He asked the man to choose from one of the three knights that were there. One of the knights was the Knight of Life, and he always told the truth. The second Knight was the Knight of Death, and he always told lies. The third knight was the Knight of the Dungeon. He sometimes lied and sometimes told the truth. If the man chose the Knight of Death, he would be executed before sunset. If he chose the Knight of Life, he would be acquitted and set free right away. If he chose the Knight of the Dungeon, he would spend the rest of his life imprisoned in the Dungeon. The man was allowed to ask the three knights one question each.

Thus, he asked the fat knight, "What is the name of this tall knight?" The reply was, "He is the Knight of Life." He asked the small knight, "What is the name of this tall knight?" The reply was, "He is the Knight of Death." Then he asked the tall knight, "Who are you?" "I am the Knight of the Dungeon" was the reply. After that, the man was able to correctly choose the Knight of Life, and was set free immediately.

Who is the Knight of Life, and who are the other two knights?

Solution

title: Puzzles/Logic puzzles/Three Knights


text:
Puzzles/Logic puzzles/Three Knights/Solution

Puzzles | Logic puzzles | Three Knights | Solution

The small knight is the Knight of Life. The fat knight is the Knight of the Dungeon. The tall knight is the Knight of Death.

Reasoning
The tall knight is not the Knight of the Dungeon, since if he were neither of the other knights could be the Knight of Life. Since he lied, he is not the Knight of Life. Therefore, the tall knight is the Knight of Death. The small knight must then be the Knight of Life, leaving the fat knight as the Knight of the Dungeon.

Provided the fat knight tells the truth he can not be the Knight of Life as he is pointing out the tall knight as Knight of Life. The answer of the tall knight contradicts the answer of the fat knight. Therefore, the fat knight was lying. The tall knight can not be the Knight of Life, because he would have said so when directly asked, who he is. We can conclude that the small knight is the Knight of Life and he is pointing out the tall Knight as Knight of Death as he is always telling the truth. The last job position left for the fat knight is the Knight of Dungeon.

The convict can be happy that the tall knight did not answer: 'Yes, I am the Knight of Life'. In this context, it would have been possible and would have left our convict very unfortunate, because his chance to find the Knight of Life would have been reduced by 50%

A better tactic would be to ask each Knight: "If I asked you who the Knight of Life was, whom might you identify?" The Knight of Life would correctly identify himself. If asked "Who is the Knight of Life?" the Knight of Death would incorrectly identify either himself or the Knight of the Dungeon. Hence, when asked how he might respond, he would lie again, and state that he would have identified the correct Knight of Life (double negative). The Knight of the Dungeon is the unknown quantity, but when at least two Knights agree on someone, that is the correct identification.

Unfortunately not foolproof, as if he would have identified the Knight of the Dungeon for his first lie, he could then pick to instead identify the Knight of Death for his second lie.


text:
US History/Introduction

Presentation
&nbsp ;

Content and Contributions
This is, to the best of our knowledge, the world's first open content US History Textbook. The users are invited to tweak and refine this book until there is nothing better available. The authors are confident that this will happen because of the success of the Wikipedia site.

title: US History/Introduction


text:
Talk:Spanish/Typing Spanish Characters

 * I use Windows 98SE, and I've noticed that, instead of typing in Alt+a to get á, I have to type in Ctrl+a. Is this version-specific? Internet Explorer users who have Microsoft Word 2000 installed can consult mk:@MSITStore:c:\Program%20Files\Microsoft%20Office\Office\1033\wdmain9.chm::/html/wohowTypeInternationalLetters.htm. -- Minh Nguyen 2003-09-18 22:15 (EDT)

title: Talk:Spanish/Typing Spanish Characters


text:
Python Programming

This book describes Python, an open-source general-purpose interpreted programming language available for the most popular operating systems. The current versions are 3.x while versions 2.x are no longer supported, since 2020. This book describes primarily the versions 3.x, but does at times reference versions 2.x.

There are a few implementations for Python 3 (and older): the standard implementation written in C, and PyPy, a JIT-compiled version written in RPython - a subset of Python. For Python 2 only there are Jython written in Java and IronPython written in C# for the .NET environment.

Intro

 * /Overview/
 * /Getting Python/
 * /Development Environments/
 * /Interactive mode/
 * /Self Help/

Basics

 * /Creating Python programs/
 * /Variables and Strings/
 * /Basic syntax/
 * /Sequences/ (Strings, Lists, Tuples, Dictionaries, Sets)
 * /Data types/
 * /Numbers/
 * /Strings/
 * /Lists/
 * /Tuples/
 * /Dictionaries/
 * /Sets/
 * /Basic Math/ -- redundant to "Operators"
 * /Operators/
 * /Control Flow/
 * /Decision Control/
 * /Conditional Statements/
 * /Loops/
 * /Functions/
 * /Scoping/
 * Input and Output
 * /Files/
 * /Modules/
 * /Classes/
 * /Exceptions/
 * /Errors/
 * /Source Documentation and Comments/
 * /Idioms/
 * /Package management/
 * /Python 2 vs. Python 3/

Advanced

 * /Decorators/
 * /Context Managers/
 * /Reflection/
 * /Metaclasses/
 * /Performance/
 * /PyPy/
 * /Cython/
 * /Command-line one-liners/
 * /Tips and Tricks/

Standard library modules

 * /Standard Library/
 * /Regular Expression/
 * /External commands/
 * /XML Tools/
 * /Email/
 * /Threading/
 * /Sockets/
 * /GUI Programming/
 * /Tkinter/
 * /CGI interface/
 * /WSGI web programming/
 * /Internet/
 * /Networks/
 * /Math/

Third-party modules

 * /Databases/ -- to be merged with the following chapter
 * /Database Programming/
 * /numpy/
 * /Game Programming in Python/
 * Qt4
 * /Dbus/
 * /pyFormex/
 * /matplotlib/
 * /Sorted Container Types/
 * /Excel/
 * /MS Word/

Writing extension modules

 * /Extending with C/
 * /Extending with C++/
 * /Extending with Pyrex/
 * /Extending with ctypes/
 * /Extending with Perl/

Appendices

 * /Popularity/
 * /Links/
 * /Authors/
 * /Library Modules/
 * /Naming conventions/

title: Python Programming


text:
Puzzles/Hard Sequence 1/Solution

The answer is 76.

Rule: T    T=L²+LR+1 mod 100 L R

title: Puzzles/Hard Sequence 1/Solution


text:
Puzzles/Hard Sequence 2/Solution

The answer is 68.

Rule: T    T=L²-LR+1 mod 100 L R

title: Puzzles/Hard Sequence 2/Solution


text:
Puzzles/Logic puzzles/Pizzas

Puzzles | Logic puzzles | Pizzas

Aaron, Betty, Charlie, Debbie, and Eric each ordered a pizza with three of the following five toppings: green pepper, mushrooms, onions, pepperoni, and sausage. The only topping that Aaron and Charlie had in common was sausage. The only topping Debbie and Eric had in common was pepperoni. The only topping Charlie and Betty had in common was mushrooms. The only topping Debbie and Betty had in common was green pepper.

Which toppings did each of them have on their pizza?

Solution

title: Puzzles/Logic puzzles/Pizzas


text:
Puzzles/Logic puzzles/Pizzas/Solution

Puzzles | Logic puzzles | Pizzas | Solution

Aaron - green pepper, onions and sausage

Betty - green pepper, mushrooms and onions

Charlie - mushrooms, pepperoni and sausage

Debbie - green pepper, pepperoni and sausage

Eric - mushrooms, onions and pepperoni

Reasoning
We are informed that B and D had green pepper, B and C had mushrooms, D and E had pepperoni and A and C had sausage, all marked with a Y.

| A | B | C | D | E Green Pep |   | Y |   | Y | Mushrooms |  | Y | Y |   | Onions   |   |   |   |   | Pepperoni |  |   |   | Y | Y  Sausage   | Y |   | Y |   |

We are also informed that the pairs B and D, B and C, D and E, and A and C, didn't share anything, except what is already marked with a Y. This eliminates the possibilities marked with an N.

| A | B | C | D | E Green Pep |   | Y | N | Y | N  Mushrooms | N | Y | Y | N | Onions   |   |   |   |   | Pepperoni |  | N |   | Y | Y  Sausage   | Y | N | Y |   |

Knowing everyone had 3 toppings allows us to place another Y.

| A | B | C | D | E Green Pep |   | Y | N | Y | N  Mushrooms | N | Y | Y | N | Onions   |   | Y |   |   | Pepperoni |  | N |   | Y | Y  Sausage   | Y | N | Y |   |

And we know B didn't share with C or D.

| A | B | C | D | E Green Pep |   | Y | N | Y | N  Mushrooms | N | Y | Y | N | Onions   |   | Y | N | N | Pepperoni |  | N |   | Y | Y  Sausage   | Y | N | Y |   |

Allowing us to place 2 more Ys.

| A | B | C | D | E Green Pep |   | Y | N | Y | N  Mushrooms | N | Y | Y | N | Onions   |   | Y | N | N | Pepperoni |  | N | Y | Y | Y  Sausage   | Y | N | Y | Y |

D didn't share with E, A didn't share with C.

| A | B | C | D | E Green Pep |   | Y | N | Y | N  Mushrooms | N | Y | Y | N | Onions   |   | Y | N | N | Pepperoni | N | N | Y | Y | Y Sausage   | Y | N | Y | Y | N

This allows us to place the remaining 4 Ys.

| A | B | C | D | E Green Pep | Y | Y | N | Y | N  Mushrooms | N | Y | Y | N | Y  Onions    | Y | Y | N | N | Y  Pepperoni | N | N | Y | Y | Y  Sausage   | Y | N | Y | Y | N

Surprisingly, no one chose green pepper, onions and pepperoni.

title: Puzzles/Logic puzzles/Pizzas/Solution


text:
Talk:Puzzles/Logic puzzles/Pizzas/Solution

Very nice, Cyp. The solution is very clear and easy to follow. Thomas


text:
Talk:Internet Technologies

About

 * Started: 6 August 2003
 * Size: 11,800 words (Sep 2008)

Various
Gmasters2: The outline of this book is a great start! Networking is very difficult to teach to high school students in the vocational setting because of the high readability level of traditional textbooks. Further compounding the teaching of networking to high school students in the voc-tech high school is the learning style of many of the students. I teach networking in a voc-tech high school where the students are in networking 3 hours a day, 5 days a week.

The ideal curriculum is certification-based, meaning that the competencies taught meet the requirements set forth by national/international certification bodies, such as CompTIA and others. This is critical as the goal of the voc-tech high shcool is twofold: 1) prepare students for employment upon course completion, and 2) serve as a link to more advanced training at the community college or university level.

Currently, I am using a commercially-produced curriculum produced by Course Technologies that provides training in networking qualifying the students to sit for the CompTIA i-Net+ and Network+ certifications. I also teach Linux to prepare students for the CompTIA Linux+ certification.

The thrust of the programs is lab-based. Students today demand interactive texts and the Internet is perhaps the best way to deliver the material. The only downsides to commercial programs are that they are not always "chunked" into modules that lend themselves to high school students.

I'm willing to submit a course outline that could form the basis of a full-fledged i-Net+ high school curriculum.

Guest: What is the difference between this project and the wikipedia? Should we copy definitions of all of these net services from the wikipedia as a starting point? In what way will we need to edit that content to make it more "textbook" like?

 * Add exercises, questions, don't interlink everything... r3m0t 14:21, 31 Dec 2003 (UTC)
 * What is the difference between this project and the wikipedia? - exactly! As written, this page is far too technical and un-interesting for students - it is basically a wikipedia definition. don't interlink everything - exactly. I have removed the stupid year links for a start. -Drstuey 00:33, 5 Sep 2004 (UTC)

[User:PbS]: Ok so I added some stuff to VNC, and SSH. Is this kind of what you guys are looking for? PbS 21:18, 22 Aug 2004 (UTC)

[User:Epl18]:I'm for deleting everything that has a better wikipedia entry, like email and IRC. Epl18 14:02, 30 August 2005 (UTC)

Possible topics for a messenger chapter
From deleted stub "Review of Programs for Internet-based Interaction": ICQ, AOL Messenger, iVisit, MSN Messenger, PalTalk, Skype, Windows Messenger, Yahoo Messenger --Kernigh 20:08, 15 April 2006 (UTC)

Scope
The current scope is: --Dan Polansky (talk) 09:19, 18 September 2008 (UTC)
 * The Internet: Domain names, Web Hosting, Routing, Protocols, History and Evolution
 * The Web: History of the Web, Routing the Web, HTML and CSS (really?), Embedded technologies, Proxy servers, Search Engine, Web advertising, Online Shopping
 * Email: History of Email, Routing Email, Email headers, Email Spam, Email security
 * Usenet: History of Usenet, Routing Usenet
 * IRC
 * Remote Access: Telnet, SSH, VNC, Remote Desktop Connection

title: Talk:Internet Technologies


text:
User talk:203.130.223.162

Hi - please try and write in English if you're trying to create an article. Thanks Dysprosia 10:50, 20 Oct 2003 (UTC)

title: User talk:203.130.223.162


text:
Talk:Puzzles/How do you ... ?/The Burning Island/Solution

He is stranded on the island with a flamethrower? And this flamethrower has fuel in it? And he has a lighter or matches to light the flamethrower? Wow! Talk about lucky...

Perhaps the solution should be re-worded mildly. Neolux 11:53, 20 Oct 2003 (UTC)

 * Maybe he uses the raging fire on the west end of the island to light the wood.
 * Andy M.


text:
Organic Chemistry/Book outline

Authors' To-Do Lists

Organic chemistry > Organic textbook expanded contents

Foreword
 * Purpose and mission
 * Content and contributions

Foundational concepts of organic chemistry
 * History of organic chemistry
 * Vital force theory
 * Synthesis of urea
 * Organic vs inorganic chemistry

 * Atomic structure
 * Nucleus and electrons
 * Shells and orbitals
 * Filling electron shells
 * Octet rule and exceptions
 * Molecular orbitals
 * Hybridization
 * Electron wave function

 * Ionic bonding
 * Formal charge
 * Ionization energy
 * Electron affinity
 * Electronegativity
 * Dipole moment

 * Covalent bonding
 * Molecular orbitals in bonding
 * Nonpolar covalent bonds
 * Polar covalent bonds

 * Resonance
 * Drawing resonance structures

 * Acids and bases
 * Proton donors and acceptors
 * Electron donors and acceptors
 * Electrophiles and nucleophiles
 * pKa and acidity

 * Alkanes
 * Methane
 * Ethane
 * Propane thru decane
 * Stereoisomers
 * Cycloalkanes
 * Two hydrogens for every carbon
 * Cycloalkane properties
 * Naming cycloalkanes

Introduction to reactions
 * Overview of addition, elimination, substitution and rearrangement reactions
 * Polar and radical reactions
 * Redox reactions
 * Functional groups in reactions
 * Drawing reactions
 * Rates and equilibria
 * Gibbs free energy
 * Bond dissociation energies
 * Energy diagrams
 * Transition states
 * Carbocations
 * Addition reactions
 * Rearrangement reactions

Overview of Functional Groups
 * Introduction to alcohols
 * Introduction to phenols
 * Introduction to ethers
 * Introduction to epoxides
 * Introduction to aldehydes
 * Introduction to ketones
 * Introduction to carboxylic acid
 * Introduction to carboxylic acid derivatives

Alkenes
 * Alkene properties
 * Cycloalkenes
 * The pi bond
 * Stability of double bonds
 * Alkene reactions

Alkynes

Haloalkanes

Alcohols

Chirality
 * Handedness
 * Enantiomers
 * Stereogenic centers
 * Optical activity
 * Absolute and relative configurations
 * Diastereomers
 * Meso compounds
 * R-S notational system
 * Multiple chiral centers
 * Chirality beyond carbon

Dienes
 * Three kinds of dienes
 * Conjugation
 * Diene properties and reactions
 * Cyclodienes

Aromaticity
 * Other aromatic compounds

Aromatic reactions

Spectroscopy
 * Historic analytical techniques
 * Spectrometry
 * Spectroscopy proper

Organometallics

Chemistry of various functional groups

Organic chemistry and biochemistry
 * Amino acids
 * Proteins
 * Carbohydrates
 * Lipids

Periodic table
 * Valence
 * Bonding:
 * Electronegativity
 * Hybridization

Lewis structures
 * Resonance
 * Formal charges
 * Conjugation
 * Aromaticity

Nomenclature
 * Alkanes
 * Cycloalkanes
 * Alkenes
 * Alkynes
 * Haloalkanes
 * Alcohols

Isomers
 * Structural isomers
 * Stereoisomers
 * Enantiomers, R, S
 * Racemates
 * Conformational
 * cis-trans
 * E, Z

Structure and properties
 * Alkanes
 * Alkenes
 * Alkynes
 * Alcohols
 * Haloalkanes
 * Arenes

Reactions
 * Alkanes (and cycloalkanes)
 * (Combustion)
 * Free radical halogenation
 * Alkenes
 * Hydrogenation
 * Hydration -> oxymercuration/demercuration
 * Halogenation
 * Hydrohalogenation
 * Hydroboration/oxidation
 * Halohydrins
 * Oxydation (Ozonolysis, osmylation, epoxidation/peroxidation)
 * Allylic bromination
 * Alkynes
 * Hydrogenation
 * Hydration
 * Halogenation
 * Hydrohalogenation
 * Ozonolysis
 * Alkylation
 * Alcohols, haloalkanes
 * Nucleophilic substitution (SN1, SN2)
 * Elimination (E1, E2)
 * Carbocation rearrangements
 * Conjugated (1,3-) dienes
 * Direct (1,2-) and conjugate (1,4-) addition
 * Kinetic and thermodynamic control
 * Diels-Alder reaction
 * Aromatic compounds
 * Hydrogenation
 * Ozonolysis
 * Benzylic bromination
 * Benzylic oxydation
 * Vinylic benzenes (styrenes)

Chirality
 * Cahn-Ingold-Prelog nomenclature of chiral atoms

title: Organic Chemistry/Book outline


text:
Puzzles/Arithmetical puzzles/Luxury Cars

Puzzles | Arithmetical puzzles | Luxury Cars

A major luxury car company has three outlets on the east coast (in New York, Boston, and Miami) and two outlets on the west coast (in Los Angeles and San Francisco). The sales in Los Angeles were one quarter of the total sales plus one car. The sales in New York were one quarter of the rest (not counting the cars sold in L.A.) plus one car. The sales in San Francisco were one quarter of the rest (not counting L.A., N.Y.) plus one car. And the sales in Boston were one quarter of the rest (not counting L.A., N.Y., S.F.) plus one car. The balance so far showed that L.A. and San Francisco sold 100 cars more than N.Y. and Boston. However, with the remaining cars sold in Miami it is likely that the total sales of the east coast will be greater than the total sales of the west coast.

How many cars were sold in each city?

solution


text:
Puzzles/Geometric Puzzles/Connecting Utilities

Puzzles | Geometric puzzles | Connecting Utilities

Here is a problem; you are commissioned to connecting utilities to the three houses A, B, and C below. The utilities are G for gas, W for water, and E for electricity.

/-\'     /-\'      /-\'      |A|       |B|       |C| -    -     -

[G]      [W]       [E]

You must connect each house to each utility without the connections crossing at all.

Solution


text:
Puzzles/Geometric Puzzles/Connecting Utilities/Solution

Puzzles | Geometric puzzles | Connecting Utilities | Solution

This problem can be analyzed using graph theory.

The problem is essentially showing that the bipartite graph K3,3 is planar. However, Kuratowski ' s theorem tells us that this graph must not be planar.

Essentially, there is no solution and the required construction cannot be done! Sorry! :)

However, if we look at where the three houses and utilities are on a non-planar surface, such as a torus (or doughnut), we obtain some topological niceties that allow us to solve this problem.

Here is an example of one solution. Lines moving off the torus and looping around are signified with a V.

\   | |  |    |      /  |       ==V===V=V==V====V=====V===V====== : |  |  \  \   |    /    |     :  : |  /-\' | |  /-\'  |   /-\'   :  : |  |A|  | |  |B|   |   |C|    : : | - | | - |  -   :  : |__/ |  |  \_| |___/   | |    :  :      |   \____________/  |    :  :      \______     ________/    :  :             \   /             :  :              | |              :  :    [G]---\   [W]       [E]    : :    | \  |    |       / | \   :  ======V=V==V=====V=====V==V==V=== | | |    |     /   |   \

Here is a picture with forks, essentially equivalent to parallel connections

The solution usually given to this puzzle depends upon the fact that the puzzle, as stated, does not prohibit one of the connections going under a house (for example, the gas connection for A is routed G->pass under B->A). This appears to be topologically equivalent to the above(?).


text:
User:Traroth

Nobody here anymore.

title: User:Traroth


text:
Talk:French/Vocabulary/Nations

Untitled
There exists a difference between Dominica and the Dominican Republic. The Republic is a part of the island of Hispaniola, the latter is a separate island. Thus, it would be incorrect to call "Dominica" the "la République dominicaine," as that title would go to the Dominican Republic. Lord Emsworth 10:35, 21 Oct 2003 (UTC)

You're right. I make a mistake. Traroth 11:04, 21 Oct 2003 (UTC)

title: Talk:French/Vocabulary/Nations


text:
User talk:Traroth

Nobody here anymore.

title: User talk:Traroth


text:
Polish/Some useful expressions

^ Polish ^ > Polish pronunciation >

As an initiation to Polish it's useful to know a few common expressions:

 * Dzień dobry - good day (jane DOH-brih)
 * Dobry wieczór - good evening (DOH-brih VYEH-choor)
 * Dobranoc - good night (doh-BRAH-notes)
 * Cześć - hello (cheshch)
 * Do widzenia - good bye (doh vee-DZEN-ya)
 * Proszę - please / here you are (PROH-sheh)
 * Dziękuję - thank you (jen-KOO-yeh)
 * Dzięki - thanks (informal) (JEN-kee)
 * Przepraszam - I'm sorry / excuse me (psheh-PRAH-shahm)
 * Tak - yes (tahk)
 * Nie - no / not (nyeh)
 * Nie wiem - I don't know (nyeh vyem)
 * Jak się masz? - How are you? (informal) (yahk shay mahsh)
 * Nie mówię po polsku. - I don't speak Polish (nyeh MOO-vyeh poh pohl-skoo)
 * Nie rozumiem - I don't understand (nyeh roh-ZOO-myem)
 * Na zdrowie! - Cheers! / Bless you! (lit. For health!) (nah ZDROH-vyeh)

^ Polish ^ > Basic sentences 1 >

]

title: Polish/Some useful expressions


text:
Polish/Basic sentences 1

^ Polish ^

 * Co to jest? / tso to yest / - What is it/this?

This question is used to ask about things/objects and refers mostly to both plural and singular, although the answers vary depending on the number:

 * To jest ... / to yest / > This is...
 * To są .../ to sõ / > These/Those are...

eg. " - Co to jest?" " - To jest książka." / to yest kshõshka / > This is a book.

" - Co to jest?" " - To są książki." / to sõ kshõshki / > These are (some) books.

To get information about a person, you need to use "kto?" / who? /:
 * Kto to jest? > Who is it?

The possible answers are:
 * To jest...- in singular
 * To są...- in plural

eg. " - Kto to jest?" " - To jest człowiek." /to yest chwovyek/ This is a man/human. " - Kto to jest?" " - To są ludzie." /to sõ looje/ These are people.

The following sentences may be employed to introduce your family or friends to someone:

 * moja mama > my mom
 * mój tata > my dad
 * moja siostra / shostra / > sister
 * mój brat > brother
 * mój kuzyn / koozin / > cousin (male)
 * moja kuzynka / koozinka / > cousin (female)
 * moje dziecko / jetsko / > child
 * To jest moja rodzina. > This is my family.

< Polish pronunciation < ^ Polish ^ > Basic Polish sentences 2 >

Polonês/Índice/Frases básicas 1

title: Polish/Basic sentences 1


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Polish/Polish pronunciation

^ Polish ^ < Some useful expressions >

Polish pronunciation is rather regular. Once you learn the rules, you should be able to guess how a word is pronounced and get it more or less right even if you've never heard it before (unlike English which is rather unpredictable).

Vowels are pronounced similarly to their counterparts in most other European languages (not English though) but note, there are no long vowels.

Stress is almost always on the penultimate (next-to-last) syllable.

(b d f h k l m n p t z are pronounced as you'd expect them to be.)

Special letters are:

Special letter combos are:

 * In most cases, vowels are pronounced separately, for example, stoi, moi, twoi, nauczyć, zaufać, (to milk),  (Ukraine),  (name of a region),  (atheist)
 * Vowel combos right at the beginning of a word are typically pronounced as a diphthong (these are generally loanwords). For example, (personal name),  (autograph),  (Europe).

 * If you don't know how to pronounce hard/soft pairs ( (liquid) ) you can use the same form and you will usually be understood. Note: While the rule seems to be effective in most cases, the word ciecz might not be the best example for it. If you end up pronouncing it so that is sounds similar to cieć (pronounced "ćeć", colloq. janitor), you may get funny looks, especially from older speakers (due to the humorous context it had in the old comedy series Alternatywy 4).

 * Doubled consonants are pronounced individually or lengthened, for example, (daily),  (receptive), lekki (light), oddech (breath), dziennik (daily newspaper), zza (from beyond, behind), greccy ("Greek", masculine, plural, nominative adjective), or ssak (mammal).

Devoicing is not something you need to focus on but you should be aware of it.
 * You may also notice something called final devoicing, for example:
 * chodź (come!) sounds like choć (although) : (be {imperative})
 * final ż sounds more like sz : (because, since),  (although)
 * final b → p : (method)
 * final g → k : (train)
 * final d → t : (error),  (from over there)
 * final w → f : (puff),  (first)
 * final z → s : (sensibly)

Vowel Reduction in Polish Language
Vowel reduction is a significant aspect of the phonological system of the Polish language. It refers to the phenomenon where vowels in unstressed syllables undergo changes in quality.

The Nature of Vowel Reduction
In Polish, vowel reduction primarily occurs in unstressed syllables. The full vowels /a/, /e/, /i/, /o/, /u/ and /y/ can be reduced when they are not in the stressed position. The sound of a word changes according to vowel reduction when unstressed vowels are pronounced differently than stressed vowels. Unstressed vowels are often reduced to a schwa sound (a neutral vowel sound like the "e" in "the"), while stressed vowels are pronounced more clearly and with their full vowel sound. This can affect the overall pronunciation of a word and can make it sound quite different when spoken in context. The exact nature of the reduction can depend on a variety of factors, including the phonetic environment, the speed of speech, and individual speaker variation.

Examples of Vowel Reduction
Here are some examples of vowel reduction in Polish:

 * In the word 'kotek' (kitten), the 'e' is reduced, often pronounced closer to [i].
 * In the word 'lampa' (lamp), the second 'a' is reduced, often pronounced closer to [ə].

Factors Influencing Vowel Reduction
Several factors can influence the occurrence and degree of vowel reduction in Polish:

 * **Position in the word**: Vowels in final position are often reduced.
 * **Speech rate**: In fast speech, vowel reduction is more likely to occur.
 * **Individual variation**: Different speakers may reduce vowels to different degrees.

title: Polish/Polish pronunciation


text:
Polish/More on nouns - genders

Depending on the classification chosen, there are either three or five genders in Polish:
 * Masculine (męski)
 * Masculine personal (męski osobowy)
 * Masculine animate (męski nieosobowy żywotny)
 * Masculine inanimate (męski nieosobowy nieżywotny)
 * Feminine (żeński)
 * Neuter (nijaki)

In the plural, męskoosobowy (masculine-personal) and niemęskoosobowy (non-masculine-personal) are used for masculine personal nouns and the remaining ones respectively.

Unlike German, and more like Italian, it is usually possible to determine the gender of a noun by looking at its ending and meaning.
 * Nouns that end in -a are usually feminine.
 * Exceptions include words that end in -ista, which indicate followers of some ideology (like komunista, communist) - they are considered person-masculine.
 * Nouns that end in -awca/-owca and describe professions (like sprzedawca, salesman; kierowca, driver) are also considered person-masculine.
 * An exception is the word "mężczyzna," which means "adult male person" and is obviously person-masculine.
 * Some other masculine words include "tata" (dad), "poeta" (poet), and "sędzia" (judge).
 * Some words that end in a consonant are feminine, such as gałąź (branch), jesień (autumn), łódź (boat or a Polish city), myśl (thought), noc (night), podróż (journey), pomoc (help), postać (figure), północ (north and midnight), rzecz (thing), sól (salt), twarz (face), and wieś (countryside).
 * Their declension is quite similar to that of feminine nouns ending in "-a".
 * Nouns that end in -ść are usually feminine.
 * They are often abstract nouns, such as miłość (love, from the adjective miły, nice, in old Polish "loved") and wysokość (height, from the adjective wysoki, high).
 * Nouns that end in -o, -e, -ę, or -um are usually neuter.
 * Examples include dziecko (child), zawiniątko (package), jedzenie (food), wyjście (departure, exit, solution), zwierzę (animal), and muzeum (museum). NOTE: Some nouns ending in -e are plural and require plural verbs, such as grabie (rake), Katowice, nożyce (scissors), skrzypce (violin), spodnie (pants), and szczypce (pliers).
 * Most other nouns ending in a consonant are masculine, and their exact gender depends on their meaning. The most common exceptions are animate-masculine nouns that aren't truly animate, especially in spoken language.
 * Nouns that end in -i or -u in the nominative singular are rare and mostly of foreign origin. Native Polish words ending in -i are feminine, such as gospodyni (hostess or farmer's wife) or pani (lady). NOTE: Some nouns ending in -i are plural and require plural verbs, such as drzwi (door), Helsinki, nożyczki (scissors), and obcęgi (tongs).

Now, here are some examples:

 * "Adam pije kawę" - Adam drinks coffee.
 * "Kasia widzi Adama" - Kasia sees Adam.
 * "Kot pije mleko" - A cat drinks milk.
 * "Adam widzi kota" - Adam sees a cat.
 * "Adam ma komputer" - Adam has a computer.

< Polish pronunciation < ^ Polish ^

title: Polish/More on nouns - genders


text:
Organic Chemistry/Introduction to reactions/Oxidation reactions

Intro to oxidation reactions
'''Oxidation reactions involve electron loss in the moeity of interest. ''' When iron rusts, iron atoms lose electrons to oxygen molecules, and is said to undergo oxidation.

Ozonolysis
This is one of the simplest and easiest reaction mechanisms to learn. In ozonolysis, a carbon-carbon double bond is split in two by reaction with ozone. The two products, which can be aldehydes or ketones, each have one oxygen atom double bonded to each of the two carbons that had made up the double bond. The ozone (O3) cuts right thru the carbon-carbon double bond and leaves oxygens double bonded to the two newly severed ends.

that is,

Osmylation
In this reaction, a carbon-carbon double bond turns into a single bond with one hydroxy group attached to each of the two carbons.

When heated, this product splits into two ketones (each of the two carbons ends up double bonded to the oxygen in the hydroxy group).

Epoxidation (peroxidation)
This reaction uses peroxides (an oxide with an extra linked oxygen) to produce epoxides.


text:
Organic Chemistry/Introduction to reactions/Reactions

 * Alkanes
 * Combustion
 * Free-radical halogenation
 * Alkenes
 * Hydrogenation adds H2
 * Hydrolysis adds H2O
 * Oxymercuration/demercuration
 * THF
 * Halogenation adds halogen
 * Hydrohalogenation adds H and a halogen
 * Hydroboration
 * Halohydrins
 * Oxidation reactions
 * Allylic bromination
 * Diels-Alder reaction
 * Alkynes
 * Hydrogenation adds H
 * Hydration adds OH
 * Halogenation adds a halogen
 * Hydrohalogenation adds H and a halogen
 * Ozonolysis
 * Alkylation
 * Alcohols and haloalkanes
 * Carbocation rearrangements
 * Conjugated (1,3-) dienes
 * Direct (1,2-) and conjugate (1,4-) addition
 * Kinetic and thermodynamic control
 * Aromatic compounds
 * Hydrogenation
 * Benzylic bromination
 * Benzylic oxydation
 * Vinylic benzenes

Added links
 * 1) Review of nucleophilic substitution SN1, SN2
 * 2) Radicals
 * 3) Electrophilic additions
 * 4) Reactions with organometallic reagents


text:
Organic Chemistry/Introduction to reactions/Combustion

Combustion is the simplest and most basic organic reaction, so simple that it is often overlooked or taken for granted in organic chemistry texts and classes.

Combustion is the breakdown of a compound in combination with oxygen to form carbon dioxide and water. Water and carbon dioxide are both very stable and low-energy, and the atoms that make up these molecules go to form them releasing energy. This energy is heat and light that is the source for campfires and internal combustion engines.


text:
Organic Chemistry/Introduction to reactions/Hydrogenation

The result of hydrogenation reactions is to increase the number of hydrogens on a molecule. The recipient molecule is typically an alkene whose double bond is reduced by the addition of a hydrogen to each of the two carbons.

The mechanism of this reaction is usually through a catalyst, such as Nickel, Platinum (used in PtO2, otherwise known as Adams' Catalyst after Roger Adams) or Palladium (Pd) that is mixed onto an inert material like charcoal (sometimes referred to as Palladium on carbon). The reaction takes place not within a solution but actually specifically on the surface of the catalyst.

First the H2 gas is absorbed onto the catalyst surface.

The Alkene forms a complex with the catalyst surface due to the vacancy of the orbital on the metal interacting with the filled π orbital. Thus we have a structure that looks somewhat like this:

Once the complex is formed the hydrogen is able to apply itself to the double bond twice and then the final product is fully saturated and floats away from the catalyst, thus regenerating it. Hydrocarbons are of two types, aliphatic and aromatic. There are different methods to identify a hydrocarbon, if no of C atoms: 1 then Meth.


text:
Spanish/Exercises/Preterite

^Lesson 7^

Rellena los espacios en blanco - Fill in the blank
1. Colón __________ (descubrir) América en 1492.

2. Yo __________ (dejar) mi trabajo la semana pasada.

3. Anoche, los estudiantes __________ (tener) una gran fiesta.

4. Ayer, nosotros __________ (ir) a la playa.

5. El año pasado, Isabel y José se __________ (casar).

6. Ayer, Carlos no __________ (venir) a la universidad.

7. Anoche, yo __________ (mirar) la televisión.

8. Tú ________ (asistir) dos cursos esta mañana.

9. Alberto __________ (comprar) un carro el mes pasado.

10. ¡Felicitaciones! Vosotros __________ (ganar) el campeonato.

Soluciones a los ejercicios

^Lesson7^

title: Spanish/Exercises/Preterite


text:
Indonesian/Link Words

^ Indonesian ^

Dan - And

 * Saya dan Budi makan roti dan pisang-pisang - I and Budi eat bread and bananas

Atau - Or

 * Kamu mau makan atau minum? - Do you want to eat or drink?

Tapi - But
Kata ini memiliki beberapa bentuk - This has several forms
 * Tapi: Dia mau makan, tapi harus roti - S/he wants to eat, but it has to be bread
 * Tetapi: Dia mau makan, tetapi Ana tidak mau - S/he wants to eat, but Ana doesn't want to
 * Akan tetapi: Dia mau makan, akan tetapi ia tidak punya uang untuk makan - S/he wants to eat, but s/he doesn't have money for eating.

Kalau / Jika - If / When

 * Kalau kamu mau makan, makanlah - If you want to eat, go ahead and eat
 * Kalau sudah selesai makan, bereskanlah - When you finished eating, clean it up

The words Kalau and Jika are interchangeable

Karena - Because

 * Karena kamu sudah makan, kamu harus belajar - Because you've eaten already, now you have to study

Walau / Walaupun - Although / Even Though

 * Walaupun makanmu banyak, kamu tetap kurus - Even though you eat a lot, you're still thin
 * Walau malam telah larut, Joni masih mencari makan keluar - Although it was late at night, Joni still went out to look for food

Meski / Meskipun - Although
Synonymous to walau and walaupun.

Juga - Also

 * Saya juga mau makan di kantin - I also want to eat at the canteen.

Bahkan - Even/Even more so

 * Ia bahkan pergi tanpa sempat makan - S/he is even went out without having a meal first

Jadi / Maka - So/Therefore

 * Jadi, setelah ini kita mau makan kemana? - So, where do we want to eat after this?
 * Saya makan maka saya kenyang - I ate therefore I'm full
 * Makanan disini murah, maka dari itu pengunjungnya banyak - The food here is cheap, therefore it has a lot of visitors

The phrase maka dari itu is very often used to mean therefore.

Sehingga - And so / Resulting that

 * Makanku empat kali sehari, sehingga pengeluaranku bertambah - I eat four times a day, as a result my expenses have increased.

Supaya - So that

 * Saya makan supaya saya hidup - I eat so that I live

Agar - So that / In order to
Synonymous with supaya. It is often used together "agar supaya" to mean in order to, but using either one is fine.

Hanya - Only

 * Silakan makan sepuasnya, hanya jangan dibawa pulang - Please eat all you can, only don't bring any home

Saja - Only / Just)
Synonymous with hanya. However, if both are being used together as one phrase (i.e. in hanya saja), it means however, or rather "the catch is".

Lagi - Again

 * Kami pergi makan di tempat yang sama lagi - We are going to eat at the same place again

If it is used in the front of the sentence, we should use the phrase sekali lagi or lagi-lagi to mean again, or rather one more time.

 * Sekali lagi, mereka makan di restoran Italia yang sama itu - Once again, they eat at the same Italian restaurant

Lagipula - Moreover

 * Sayangnya saya tidak bisa makan lagi, lagipula makanannya sudah habis semua - It's a pity that I can eat no more, moreover, the food is all gone already

^ Indonesian ^

title: Indonesian/Link Words


text:
Indonesian/Lessons/Introduction

^ Indonesian ^ | Why Learn Indonesian? | How to use this Indonesian Wikibook >>

Why Learn Indonesian
Hi, welcome to this Indonesian tutorial.

You might be wondering why on earth you should learn Indonesian. Allow me to persuade you.

Demographic Reasons
Studying Indonesian means you can communicate with more than 240 million Indonesians, only a small percentage of whom are able to speak English. Bahasa Malaysia is also a close relative to Indonesian. You can understand both with ease since there are only minor differences in vocabulary. Therefore, learning Indonesian gives access to about 230 million people—including those in Malaysia, Singapore, and Brunei. Indonesian (or commonly called as 'Bahasa Indonesia' or simply 'Bahasa') has been taught in schools in Australia, the Netherlands, and Vietnam. In Timor-Leste, although Portuguese and Tetum are official languages, Indonesian is also important as working language as Timor-Leste was part of Indonesia from 1976 until their independence in 1999.

Practical Reasons
Indonesian is derived from Malay, a language of South Sumatra which was broadly used for trade purposes in the Malay World (now Malaysia, Indonesia, Brunei, Singapore) for centuries. When Indonesians began their fight for independence from the Dutch, the Malay language was renamed "Bahasa Indonesia" (it was renamed in 1928, while Indonesia proclaimed its independence in 1945). In Malaysia the national language is referred to as "Bahasa Malaysia". Indonesian is thus a variant of Malay.

Not even half of Indonesians are native speakers of the Indonesian language, especially those living in rural areas. Many have as a mother tongue one of a diverse array of local languages, including Javanese, Balinese, Sundanese, Madurese, Buginese, Batak, Minangkabau, or various Chinese dialects. But most Indonesians can speak Indonesian at least as a second language; it is taught in schools and understood even in the most remote islands.

What a remarkably versatile language Indonesian is! It is the language of education across the country, from the primary school to the university. It is the language of government and business administration, media, literature, and of everyday life in the big cities. It is a must for foreigners living in Indonesia. And if you are on a business trip to Jakarta, or on vacation in Bali, knowing some Indonesian can really enrich the experience. For those who are just curious language learners or those with a scholarly bent, Indonesian has an immense collection of literature.

Linguistic Reasons
Indonesian is very easy—honest! Learning it is a valuable experience in itself, and you can pick up the basics within a few weeks. Here's why it is easy:

 * No tenses. Indonesian has no tenses at all. Adding time indicators (like yesterday, next week, etc.) and aspect markers (done, in the process of, will, etc.) into your sentences will do.
 * No genders or cases. Indonesian has no genders or gramatical cases attached to the nouns. This means that there is one less rule to learn.
 * Optional plurals. Unlike in say, German, plurals are very simple in Indonesian, but also optional. You only need to repeat the noun (e.g. buku → buku-buku), or adding quantitative indicators (e.g. many, few) into the sentence (e.g. beberapa buku → some books).
 * A simple system of word formation. Indonesian has a straightforward system for combining words with prefixes, suffixes, and infixes to create new words. For example: satu means one, whereas bersatu means to unite (i.e., to make into one). This means fewer words to memorize and you can (sort of) mix-and-match words to form your own word. The catch is that some words cannot be combined with some prefixes or suffixes, but you'll learn that it's simple.
 * Uses the 26 letters of the Roman alphabet, which means that there is no need to relearn the alphabet, or use special software to type.
 * Consistent spelling. Indonesian is very phonetic, just like Italian. Every character is consistently spelled the same way in any word, with few exceptions. When you encounter a new word, you will always be able to pronounce it correctly.
 * No tones and simple stress patterns. Indonesian word stress typically falls on the second-last syllable of the original word, but also the last syllable and the third-last syllable. However, no matter where you put the stress, people will still recognize the word.
 * Sentence form is similar to English. Indonesian sentence structure is similar to English: Subject + Verb + [Object]. So, you can form sentences in Indonesian easily.
 * Everything is regular. Since there are no tenses, no genders, and simple plurals, everything is regular. Even the word-formation system is regular with some simple rules. You don't need to memorize lots of exceptions.

I hope now you can see why Indonesian is worth learning.

The Catch
Now, the catch is that every language has a culture attached to it. Indonesian is no exception. Since the way Indonesian people think differs from most westerners, there are some hurdles in learning it. For example, most western people prefer active sentences, while Indonesians usually prefer passive sentences and omit the subject if it is not important.

Also, in spoken Indonesian, the formal grammatical rules are often broken by lots of shortcuts, usually specific to the region, not to mention slang words and idioms. However, all Indonesians that have finished grade school should be able to speak and comprehend proper Indonesian.

Enseignement de l'indonésien/Pourquoi apprendre l'indonésien ?

title: Indonesian/Lessons/Introduction


text:
High School Mathematics Extensions/Primes

>> Next section: Modular Arithmetic


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Organic Chemistry/Introduction to reactions/Bond dissociation energy

> Introduction to reactions

The bond dissociation energy, or bond enthalpy, for a diatomic molecule X-Y is defined as the energy required to break one mole of X-Y bonds, as illustrated in the following process...

 * X-Y(g) → X(g) + Y(g)

Bond enthalpies always refer to breaking bonds under gaseous conditions.

The mean molar bond enthalpy is an average value that is quoted for a bond that can occur in different molecular environments. An example is methane, CH4

 * CH4(g) → C(g) + 4H(g)

Bond enthalpy values are used in Hess's Law Calculations.

The standard enthalpy of a reaction can be found by considering the bond enthalpies of the products and reactants of the reaction -

 * Standard Enthalpy = Σ Enthalpy of formation of the products - Σ Enthalpy of formation of reactants

For stronger bonds, bond dissociation energy is higher as more energy is needed to break the bond.

A carbon-carbon double bond is stronger than a single bond and requires more energy to be broken. However, a carbon-carbon double bond is not twice as strong as a single one, it is only 1.5 times stronger.

All chemical bonds need an input of energy to be broken, as bonds allow a lower energy state for the component atoms. If a bond did not offer a lower energy state for the atoms that form it, a bond would not form.


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Organic Chemistry/Introduction to reactions/Rates and equilibria

> Introduction to reactions

Chemical equilibria are ratios relating the forward and backward direction of a reaction to each other. This ratio is represented by the letter K in the following equation:

K = products / reactants

Definitions
Rate of reaction is the speed at which a chemical reaction takes place, expressed as moles per unit time and unit volume. The rate r of a general reaction $$aA + bB + ... -> p P + q Q + ...$$ is defined by:

$$ r = -{1 \over a} {dC_A \over dt} = -{1 \over b} {dC_B \over dt} = ... = {1 \over p} {dC_P \over dt} =.... $$

from the expression above, it is clear that the usual convention is that reaction rate is taken as products formation rate.

Rate is a function of the concentration of reactants and products, temperature, pressure and presence of a catalyst.

Rate expression
A common expression for reaction rate is the power law:

$$r = k C_A^ \alpha\ C_B ^ \beta\ ....$$

$$k$$ is called the kinetic constant, and $$ \alpha\ $$, $$ \beta\ $$, etc. are called the reaction order with respect to the reactant A, B (or the partial order of A, B etc.), respectively. The sum of all the orders is the global order of the rate expression. Therefore the rate expression $$ r = k C_A C_B $$ is a second-order and first-order in A and B.

The reaction orders are the same as the stoichiometric coefficient in the case of an elementary reaction only; in most cases they must be determined experimentally and are valid in the window of experimental conditions.

Elementary data on reaction orders can be obtained by changing the concentration C of one of the reactant, say A, and measuring the initial rate r. Plotting a rate vs concentration log-log graph, one obtains a straight line whose slope is the partial order in—say—A by virtue of the relation $$ log \, r = log \, k C_A ^ \alpha\ = log \, k + \alpha\ log \, C_A $$

Influence of temperature and pressure
$$ k = k_0 exp \left ( - \Delta\ G^{*} / RT \right)$$

as known as the Arrhenius equation

Rate equations and reaction mechanisms
The most important research application of kinetic investigations is the determination of reaction mechanisms. In fact, the rate expression is function of it.

From a postulated reaction mechanism (the model), a rate equation can be derived and used to analyse the experimental data. If the obtained fit is not statistically significant, the scheme is rejected. In complex systems, several schemes can produce compatible rate expressions and the problem of model discrimination is of primary importance.

Limiting step
Often a reaction has two or more steps. One of the steps, usually the last one, is the slowest step, and is said to be rate-limiting.

Steady state approximation
Sometimes it is useful, when calculating the reaction rate, to assume that no particular step is rate-limiting. Instead, the reaction intermediate can either proceed to the product or return to the original reactant with an equal rate for either possibility. This is called the steady-state approximation.

Example
A classical example is the hydrolysis of haloalkanes:

 * R-X + H2O → ROH + HX

This reaction can occur by two mechanisms: the SN1 and SN. The former is a unimolecular substitution: its rate is determined only by the concentration of R-X, without regard to the concentration of the new substituent. The latter is bimolecular: its rate is first-order in both R-X and new substituent, for a combined rate order of 2.

Equilibrium
Chemical equilibrium is the state when a net reaction is neither going forward nor backward. It is a dynamic equilibrium. The rate of the forward reaction equals the rate of the reverse reaction, so the two cancel each other out, and the net rate of change is zero.

The chemical equilibrium is dictated by the equilibrium constant (often written Keq), expressed by the mass-action law:

$$ K_{eq} = \frac { \prod_{i \in products} C_i}{ \prod_{j \in reactants} C_j } $$

The concentration C can be expressed in any scale, e.g. molar franction, molarity, partial pressure.

If the temperature and pressure are kept constant, no matter what are the initial concentrations, the system will evolve until the mass-action product is equal to the Keq. In general, systems with $$K_{eq} \ll 1$$ are highly displaced to the reactant sides (almost no conversion at equilibrium), whereas when $$K_{eq} \gg 1$$ the reaction goes to completion.

From classical thermodynamics it can be showed that the following relation holds:

$$K_{eq} = exp \left( -{\Delta\ G_R}/{RT} \right)$$

where $$\Delta\ G_R$$ is the total change in Gibbs free energy with reaction (product minus reactants).

Influence of temperature
The influence of temperature can be obtained by differentiation of the equation above to lead:

$$ -ln K_{eq} = \frac {\Delta\ H_R} {RT} - \frac {\Delta\ S_R}{R}$$

as known as the van't Hoff equation. Therefore, for exothermic reaction ($$\Delta\ H_r < 0 $$) an increase in temperature will decrease the $${\Delta\ H_R}/{RT}$$ quantity, leading to a lower Keq, conversely for an endothermic reaction.


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Organic Chemistry/Introduction to reactions/Energy diagrams

> Introduction to reactions

Energy diagrams are used to show the favorability of a reaction. They show how energy gained or lost in the different stages of a reaction and show which stages are the slow and fast steps (slow steps have high potential energy). We can also compare the energies of one reaction to another in order to see which reaction will be favored.

Transition states are high peaks in an energy diagram.

If the end of the diagram is lower than the beginning, the product of the reaction is more stable and/or lower in energy than the starting materials, and the overall reaction is energetically favorable. If the tail end of the energy diagram is higher than the front, then the product is less stable or energetically favorable than the starting materials, and the overall reaction is energetically unfavorable. Any high peaks in the diagram indicate difficult points to pass and will slow down the reaction.


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User:Mxn

English Wikipedia | Wikipedia en Español | Simple English Wikipedia | Wikipedia Tiếng Việt | Wiktionary -

A software developer and Stanford University alumnus in California, United States. You can find out more about him at his Wikipedia user page or his website.

Current work

 * Wikibooks tiếng Việt [vi] – Vietnamese Wikibooks
 * Vietnamese [en,vi] – Vietnamese textbook in English
 * Vietnamita [es,vi] – Vietnamese textbook in Spanish

title: User:Mxn


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User talk:Mxn

Welcome Mxn, I hope you enjoy your time here. BTW I graduated from UC not so long ago down there in your fair city. I checked out your links and saw your Vietnamese language work there on your site. Any plans to put some of that up on this site ? (That would be awesome if you did). --Karl Wick

Hi Minh and welcome to Wikibooks. I'm really excited to see that you are making edits for the Spanish Wikibook! Thomas

Main page
Hello again, I noticed that you undid my change to the main page without comment. Could you comment ? --Karl Wick
 * Oh wait .. am I totally confused ? Sorry if so ... I should have some lunch maybe ...
 * Yeah I'm spaced. Sorry, anyways hope things are nice down there in Cincy, I was just there a couple weekends ago to enjoy a graduation in the family. Too much snow up here in Cleveland right now. --Karl Wick

 * Hehe, that's okay. It's fine here in Cincinnati, just bitterly cold. But I gather it's a bit colder up there in Cleveland.  – Minh Nguyễn 19:56, 15 Jan 2004 (UTC)

Người Việt
Chào anh! Thật vui vì tìm được một người cùng xứ trên wikibook tiếng Anh này. Em mới biết đến các dự án wiki và cảm thấy đây là những dự án rất có ích. Tuy nhiên em đã bỏ công "tìm" nhiều mà vẫn không "hiểu" được cách hoạt động của các dự án wikibook, wikiversity (trình độ tiếng Anh của em không tốt lắm). Anh có thể giải thích giùm em được không?

Nhân tiện anh có phải chủ dự án wikibook tiếng Việt? Em thấy wikibook tiếng Việt mình có nhiều bài viết còn sơ sài và hình như mọi người vẫn chưa hiểu cách viết Wikibook và các phần mềm wiki (giống như em).

Nếu có thể xin hãy bỏ chút thời gian trả lời câu hỏi ngốc nghếch này của em nhé! Cảm ơn.

—The preceding unsigned comment was added by Cumeo (talk • contribs) 04:32, 12 May 2007 (UTC).

 * Xem User talk:Cumeo.

title: User talk:Mxn


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Organic Chemistry/Introduction to reactions/Hydrohalogenation

A simple alkene undergoing hydrohalogenation

Alkenes are electron-rich. Just look at those electrons all clumped together in the carbon-carbon double bond. They act as Lewis bases (they give up electrons).

Hydrohalogenation follows Markovnikov's rule. That is, the carbon of the double bond that starts out more substituted receives the halogen (becomes more substituated) while the carbon of the double bond that starts out less substituted ends up with the hydrogen.

''He who has, gets: This is another alkene illustrating hydrohalogenation. Notice how the more highly substituated carbon ends up with the X-''

The H+ is attracted to the electron-rich double bond and adds first, on the carbon with more hydrogens, leaving the other carbon with a positive charge (a carbocation). Then the X- reacts with the carbocation.

Read about Vladimir Vasilevich Markovnikov on Wikipedia.


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User talk:129.186.19.28

Hi :) Nice work you're doing here! Have you considered getting a username? Thanks Dysprosia 23:22, 22 Oct 2003 (UTC)

title: User talk:129.186.19.28


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Calculus/Series

Introduction
A series is the sum of a sequence of terms. An infinite series is the sum of an infinite number of terms (the actual sum of the series need not be infinite, as we will see below).

An arithmetic series is the sum of a sequence of terms with a common difference (the difference between consecutive terms). For example:
 * $$1+4+7+10+13+\cdots$$

is an arithmetic series with common difference 3, since $$a_2-a_1=3$$, $$a_3-a_2=3$$, and so forth.

A geometric series is the sum of terms with a common ratio. For example, an interesting series which appears in many practical problems in science, engineering, and mathematics is the geometric series $$r+r^2+r^3+r^4+\cdots$$ where the $$\cdots$$ indicates that the series continues indefinitely. A common way to study a particular series (following Cauchy) is to define a sequence consisting of the sum of the first $$n$$ terms. For example, to study the geometric series we can consider the sequence which adds together the first n terms:
 * $$S_n(r)=\sum_{i=1}^n r^i$$

Generally by studying the sequence of partial sums we can understand the behavior of the entire infinite series.

Two of the most important questions about a series are:
 * Does it converge?
 * If so, what does it converge to?

For example, it is fairly easy to see that for $$r>1$$, the geometric series $$S_n(r)$$ will not converge to a finite number (i.e., it will diverge to infinity). To see this, note that each time we increase the number of terms in the series, $$S_n(r)$$ increases by $$r^{n+1}$$, since $$r^{n+1}>1$$ for all $$r>1$$ (as we defined), $$S_n(r)$$ must increase by a number greater than one every term. When increasing the sum by more than one for every term, it will diverge.

Perhaps a more surprising and interesting fact is that for $$|r|<1$$, $$S_n(r)$$ will converge to a finite value. Specifically, it is possible to show that
 * $$\lim_{n\to\infty}S_n(r)=\frac{r}{1-r}$$

Indeed, consider the quantity
 * $$(1-r)S_n(r)=(1-r)\sum_{i=1}^n r^i=\sum_{i=1}^n r^i-\sum_{i=2}^{n+1} r^i=r-r^{n+1}$$

Since $$r^{n+1}\to 0$$ as $$n\to\infty$$ for $$|r|<1$$, this shows that $$(1-r)S_n(r)\to r$$ as $$n\to\infty$$. The quantity $$1-r$$ is non-zero and doesn't depend on $$n$$ so we can divide by it and arrive at the formula we want.

We'd like to be able to draw similar conclusions about any series.

Unfortunately, there is no simple way to sum a series. The most we will be able to do in most cases is determine if it converges. The geometric and the telescoping series are the only types of series we can easily find the sum of.

Convergence
It is obvious that for a series to converge, the $$a_n$$ must tend to zero (because sum of an infinite number of terms all greater than any given positive number will be infinity), but even if the limit of the sequence is 0, this is not sufficient to say it converges.

Consider the harmonic series, the sum of $$\frac{1}{n}$$, and group terms
 * $$\begin{matrix}

\sum\limits_{n=1}^{2^m} \frac{1}{n}&=&1+\frac{1}{2}&+&\frac{1}{3}+\frac{1}{4}&+&\frac{1}{5}+\frac{1}{6}+\frac{1}{7}+\frac{1}{8}&+\ \cdots &+&\sum\limits_{p=1+2^{n-1}}^{2^n} \frac{1}{p} \\ \\ &>&\frac{3}{2}&+&\frac{2}{4}&+&\frac{4}{8}&+\ \cdots &+&\frac{2^{n-1}}{2^n} \\ \\ &=&\frac{3}{2}&+&\frac{1}{2}&+&\frac{1}{2}&+\ \cdots &+&\frac{1}{2} \end{matrix}$$ This final sum contains m terms. As m tends to infinity, so does the sum, hence the series diverges.

We can also deduce something about how quickly it diverges. Using the same grouping of terms, we can get an upper limit on the sum of the first so many terms, the partial sums.
 * $$1+\frac{m}{2}\le\sum_{n=1}^{2^m} \frac{1}{n}\le 1+m$$

or
 * $$1+\frac{\log_2(m)}{2}\le\sum_{n=1}^m \frac{1}{n}\le 1+\log_2(m)$$

and the partial sums increase like $$\log_2(m)$$, very slowly.

Comparison test
The argument above, based on considering upper and lower bounds on terms, can be modified to provide a general-purpose test for convergence and divergence called the comparison test (or direct comparison test). It can be applied to any series with nonnegative terms:
 * If $$\sum b_n$$ converges and $$0\le a_n\le b_n$$, then $$\sum a_n$$ converges.
 * If $$\sum b_n$$ diverges and $$0\le b_n\le a_n$$, then $$\sum a_n$$ diverges.

There are many such tests for convergence and divergence, the most important of which we will describe below.

Absolute convergence
Theorem: If the series of absolute values, $$\sum_{n=1}^\infty |a_n|$$, converges, then so does the series $$\sum_{n=1}^\infty a_n$$

We say such a series converges absolutely.

Proof:

Let $$\epsilon>0$$

According to the Cauchy criterion for series convergence, exists $$N$$ so that for all $$N<m,n$$ :
 * $$\sum_{k=n}^m |a_k|<\epsilon$$

We know that:
 * $$\left|\sum_{k=n}^m a_k\right|\le\sum_{k=n}^m |a_k|$$

And then we get:
 * $$\left|\sum_{k=n}^m a_k\right|\le\sum_{k=n}^m |a_k|<\epsilon$$

Now we get:
 * $$\left|\sum_{k=n}^m a_k\right|<\epsilon$$

Which is exactly the Cauchy criterion for series convergence.

$$Q.E.D$$

The converse does not hold. The series $$1-\frac12+\frac13-\frac14+\cdots$$ converges, even though the series of its absolute values diverges.

A series like this that converges, but not absolutely, is said to converge conditionally.

If a series converges absolutely, we can add terms in any order we like. The limit will still be the same.

If a series converges conditionally, rearranging the terms changes the limit. In fact, we can make the series converge to any limit we like by choosing a suitable rearrangement.

E.g., in the series $$1-\frac12+\frac13-\frac14+\cdots$$, we can add only positive terms until the partial sum exceeds 100, subtract 1/2, add only positive terms until the partial sum exceeds 100, subtract 1/4, and so on, getting a sequence with the same terms that converges to 100.

This makes absolutely convergent series easier to work with. Thus, all but one of convergence tests in this chapter will be for series all of whose terms are positive, which must be absolutely convergent or divergent series. Other series will be studied by considering the corresponding series of absolute values.

Ratio test
For a series with terms $$a_n$$, if
 * $$\lim_{n\to\infty}\left|\frac{a_{n+1}}{a_n}\right|=r$$

then
 * the series converges (absolutely) if $$r<1$$
 * the series diverges if $$r>1$$ (or if $$r$$ is infinity)
 * the series could do either if $$r=1$$, so the test is not conclusive in this case.

E.g., suppose
 * $$a_n=\frac{n!n!}{(2n)!}$$

then
 * $$\frac{a_{n+1}}{a_n}=\frac{(n+1)^2}{(2n+1)(2n+2)}=\frac{n+1}{4n+2}\to\frac{1}{4}$$

so this series converges.

Integral test
If $$f(x)$$ is a monotonically decreasing, always positive function, then the series
 * $$\sum_{n=1}^\infty f(n)$$

converges if and only if the integral

 * $$\int_1^\infty f(x)\,dx$$

converges.

E.g., consider $$f(x)=\frac{1}{x^p}$$, for a fixed $$p$$.

 * If $$p=1$$ this is the harmonic series, which diverges.
 * If $$p<1$$ each term is larger than the harmonic series, so it diverges.
 * If $$p>1$$ then

 * $$\int_1^\infty x^{-p}dx$$
 * $$=\lim_{s\to\infty}\int_1^s x^{-p}dx$$
 * $$=\lim_{s\to\infty}-\frac{1}{(p-1)x^{p-1}}\Bigg|^s_1$$
 * $$=\lim_{s\to\infty}\left(\frac{1}{p-1}-\frac{1}{(p-1)s^{p-1}}\right)$$
 * $$=\frac{1}{p-1}$$
 * }
 * $$=\lim_{s\to\infty}\left(\frac{1}{p-1}-\frac{1}{(p-1)s^{p-1}}\right)$$
 * $$=\frac{1}{p-1}$$
 * }
 * $$=\frac{1}{p-1}$$
 * }
 * }

The integral converges, for $$p>1$$, so the series converges.

We can prove this test works by writing the integral as
 * $$\int_1^\infty f(x)\,dx=\sum_{n=1}^\infty \int_n^{n+1} f(x)\,dx$$

and comparing each of the integrals with rectangles, giving the inequalities
 * $$f(n)\ge\int_n^{n+1} f(x)\,dx\ge f(n+1)$$

Applying these to the sum then shows convergence.

Limit comparison test
Given an infinite series $$\sum a_n$$ with positive terms only, if one can find another infinite series $$\sum b_n$$ with positive terms for which
 * $$\lim_{n\to\infty}\frac{a_n}{b_n}=L$$

for a positive and finite $$L$$ (i.e., the limit exists and is not zero), then the two series either both converge or both diverge. That is,
 * $$\sum a_n$$ converges if $$\sum b_n$$ converges, and
 * $$\sum a_n$$ diverges if $$\sum b_n$$ diverges.

Example:
 * $$a_n=n^{-\frac{n+1}{n}}$$

For large $$n$$, the terms of this series are similar to, but smaller than, those of the harmonic series. We compare the limits.
 * $$\lim\frac{a_n}{b_n}=\lim \frac{n^{-\frac{n+1}{n}}}{\frac1n}=\lim\frac{n}{n^\frac{n+1}{n}}=\lim\frac{1}{n^\frac{1}{n}}=1>0$$

so this series diverges.

Alternating series
Given an infinite series $$\sum a_n$$, if the signs of the $$a_n$$ alternate, that is if
 * $$a_n=(-1)^n|a_n|$$

for all n or
 * $$a_n=(-1)^{n+1}|a_n|$$

for all $$n$$, then we call it an alternating series.

The alternating series test states that such a series converges if
 * $$\lim_{n\to\infty}a_n=0$$

and
 * $$\bigl|a_{n+1}\bigr|<|a_n|$$

(that is, the magnitude of the terms is decreasing).

Note that this test cannot lead to the conclusion that the series diverges; if one cannot conclude that the series converges, this test is inconclusive, although other tests may, of course, be used to give a conclusion.

Estimating the sum of an alternating series
The absolute error that results in using a partial sum of an alternating series to estimate the final sum of the infinite series is smaller than the magnitude of the first omitted term.
 * $$\left|\sum_{n=1}^\infty a_n-\sum_{n=1}^m a_n\right|<\bigl|a_{m+1}\bigr|$$

Geometric series
The geometric series can take either of the following forms
 * $$\sum_{n=0}^\infty ar^n$$ or $$\sum_{n=1}^\infty ar^{n-1}$$

As you have seen at the start, the sum of the geometric series is
 * $$s=\lim_{n\to\infty}S_n=\lim_{n\to\infty}\frac{a(1-r^n)}{1-r}=\frac{a}{1-r}\quad\mbox{ for } |r|<1$$.

Telescoping series

 * $$\sum_{n=0}^\infty (b_n-b_{n+1})$$

Expanding (or "telescoping") this type of series is informative. If we expand this series, we get:
 * $$\sum_{n=0}^k (b_n-b_{n+1})=(b_0-b_1)+(b_1-b_2)+\cdots+(b_{k-1}-b_k)$$

Additive cancellation leaves:
 * $$\sum_{n=0}^k (b_n-b_{n+1})=b_0-b_k$$

Thus,
 * $$\sum_{n=0}^\infty (b_n-b_{n+1})=\lim_{k\to\infty}\sum_{n=0}^k (b_n-b_{n+1})=\lim_{k\to\infty}(b_0-b_k)=b_0-\lim_{k\to\infty}b_k$$

and all that remains is to evaluate the limit.

There are other tests that can be used, but these tests are sufficient for all commonly encountered series.

title: Calculus/Series


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Introduction to Philosophy

''What am I, really? Are my actions good? How can I know?'' Some of the most fundamental questions of life cannot be answered by a physical experiment. Instead, they live inside the realm of thought experiments, being examined through rigorous arguments and logic instead. The field of philosophy is broad, and the boundaries are fuzzy. In fact, some may even argue that the question of what philosophy is, is a deep philosophical question in and of itself. Even so, one common thread connects it all: philosophy is an attempt to explain our experiences and rationalize our choices in a rational, critical, and systematic fashion.

This is different from religion or doctrine, which asserts that one view and understanding of the world is the correct one, without asking for proof. But it is also different from science, in that philosophy attempts to answer those questions that fundamentally cannot be answered through physical experiments or numeric simulations. Even so, it also shares many similarities with science: both require logic and rigorous argument to understand the world. Indeed, science and philosophy go hand in hand, both depending on each other and complementing each other's strengths.

Philosophy is commonly divided into several subdisciplines or branches: the study of reasoning (logic), the study of knowledge (epistemology), the study of the features of reality (metaphysics), and the study of morality (ethics). Many other branches exist beyond these core branches, and each of these requires an introduction of its own.

It is easy to get lost in philosophy as a deep and tangled rabbit hole. It is not a discipline that gives answers plain-and-simple. In a sense, it is the art of asking the right questions, and learning things from that. As such, for the sake of introducing you to the concepts of philosophy, we will approach the subject with small, tangible steps, and instead show how to think like a philosopher before diving into deeper questions.

= Table of Contents =

Introduction

 * 1) The importance of philosophy in daily life
 * 2) But what is philosophy, really?
 * 3) The main branches of philosophy
 * 4) Thinking like a philosopher

Logic
Before we are ready to ask questions, we must first understand how to go about reasoning about them. In this chapter, we will lay out the basics of logic, the study of reasoning.

 * 1) Logic and Reason
 * 2) Truth and Validity
 * 3) Paradoxes

Epistemology
Once one starts to ask the first questions, it becomes quickly apparent that many conclusions are based on presumptions that we have simply always assumed to be correct. But how do we know for sure that those assumptions are indeed correct? What if what we believe is false? Can we verify our knowledge by critically analyzing each and every assumption we have? These, and many more such questions, form the basis of epistemology, the study of knowledge.

 * 1) What is Epistemology?
 * 2) Rationalism
 * 3) Empiricism
 * 4) Pragmatism

Metaphysics
With the unstable foundations of epistemology under our feet, and the sturdy tools of logic in our hands, we can take a look at reality itself. What is the nature of this existence we live in? How can we define the things inside? What is a person, exactly? Do we have free will? Although you may already be convinced of clear and seemingly intuitive answers for each of these questions, challenge your understanding by thinking rigorously. These deceptively simple questions quickly become very complex, and our attempts to answer them give great insight into the nature of reality. This is the realm of metaphysics, a complex field aimed at answering questions about existence itself, and many things related to it.

 * 1) What is Metaphysics?
 * 2) Ontology versus Cosmology

Ontology

 * 1) Objects and Properties
 * 2) Are People Objects?
 * 3) Emergent Properties
 * 4) Where does one object end and another object start?
 * 5) What is a Person?

Cosmology

 * 1) What is the fundamental nature of the universe?
 * 2) Determinism and randomness: does this affect free will?
 * 3) Why do we have memories of the past, but not of the future?
 * 4) Why is there something, rather than nothing?

Ethics
Building on top of the previous chapters, we now proceed to perhaps the most directly applicable discipline to our daily lives: ethics, the study of morality. What is good, and what is evil? Can something be objectively good, or is morality subjective? What choices should I make in my life? As with all such themes, these simple questions have complex, often incomplete answers. Different schools of thought build upon different core principles, and although they may appear to be similarly virtuous, the moral choices made by each of the schools of thought can conflict in fascinating ways.

 * 1) What is Ethics?
 * 2) What is a Person?
 * 3) Virtue and value-Ethics
 * 4) Consequentialism
 * 5) Deontology
 * 6) Utilitarianism
 * 7) Existentialism
 * 8) Zen Buddhism
 * 9) Transcendentalist Theology Transcendentalism
 * 10) What is Buddhist Philosophy?

Political Philosophy

 * 1) What is Political Philosophy?
 * 2) The Political Spectrum
 * 3) Introduction to Philosophy/Ancient Political Philosophy
 * 4) Middles Ages Political Philosophy
 * 5) Social Contract
 * 6) Marx and Marxists
 * 7) Liberalism
 * 8) Communitarianism
 * 9) Conservativism
 * 10) Libertarianism
 * 11) Anarchism
 * 12) Post-Politics
 * 13) Theocracies

Philosophy of Mind

 * 1) Philosophy of Mind

Aesthetics

 * 1) Aesthetics

Philosophy of Science

 * 1) Philosophy of Science

Theology

 * 1) Theology

Appendices

 * A brief history of philosophers before us
 * Authors

title: Introduction to Philosophy


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Introduction to Philosophy/Authors/MK

This book, Introduction to Philosophy, was initiated by RMK (who also plans to complete it).

The original version of the book was begun on October 22, 2003, making it the first wikibook about philosophy. Of course, this is just an outline at the moment, but "the journey of a thousand miles begins with a single step"...

title: Introduction to Philosophy/Authors/MK


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Introduction to Philosophy/What is Philosophy?

"Philosophy" is a word with numerous vastly differing definitions, ranging broadly and not always compatible with each other. Today, it is perhaps most often thought of as meaning an individual's set of guiding principles, mostly moral, that he refers to in planning out and living his life. However, philosophy as an intellectual or academic pursuit has little do with this, meaning rather something along the lines of: "The directed search for knowledge and systems of knowledge that explain topical phenomena such as the nature of existence, the causes of existence, the nature and causes of an individual, the nature and causes of knowledge itself, and a million other things."

What these million other things are constitutes the essence, or feel, of philosophy as a subject, and of what differentiates it from other kinds of directed research such as physics, biology, or even music -- all of which were at one point considered aspects of philosophy itself. As you read on, you'll develop a sense of these questions as they've evolved in the Western canon, and of how philosophy fits in with the entirety of human intellectual pursuits.

Western philosophy as we know it today is generally considered to have originated in Ancient Greece, from the people's cosmogonical or "world-creation" myths. Thales of Miletus brought back kernels of knowledge from Ancient Egypt, which over time the Greeks developed into the earliest philosophy that remains recognizably such today. It is not surprising, then, that the term "philosophy" finds its roots in the Greek language. "Philo-" stems from the Greek word philein, meaning 'to love', and "-sophy" comes from the Greek word sophia, or wisdom. Philosophy, then, can be thought of as "the love of wisdom".

Consequently, philosophers concern themselves with exploring some of the biggest questions that face humankind: What exists? What is real? What is the nature of the universe? Does God exist? Do humans have souls? What is knowledge? What is truth? How should individuals govern themselves? What is the nature of consciousness? Like many other fields of inquiry, philosophical questions spring from a certain kind of curiosity about life and reality. Much of philosophy confronts very abstract ideas and thus, unlike in other academic disciplines such as the sciences, philosophers cannot always rely on gathering empirical data through experimentation. Of course, there are numerous other techniques available to the philosopher, including formal logic, thought experiments, rational dissertation, colloquy, phenomenological analysis, and more.

[The pursuit of philosophical wisdom can be understood as a quest for two different kinds of wisdom. Aristotle characterized these as theoretical wisdom and practical wisdom. The first sort seeks understanding primarily for its own sake, whereas the latter is concerned with understanding in order to do. The distinction is not unlike those in other fields. The physicist attempts to understand matter and motion simply for the sake of extending the limits human knowledge, but the engineer attempts to understand matter and motion in order to make something useful. The philosopher who attempts to understand the metaphysical nature of the universe is concerned with a more theoretical area of philosophical inquiry, while his or her colleague who tries to understand the proper way for businesses to behave ethically, is pursuing a much more practical subject matter. Philosophy that concerns itself with these sorts of practical questions is usually called "Applied Philosophy".]

Philosophy is perhaps unique in its lack of limitation regarding subject matter. Almost every conceivable idea has been or will be tackled by philosophy, and among those that aren't, most are areas of philosophy that matured sufficiently to break off from the discipline proper and form a new field of study: physics was once called "natural philosophy." In addition, philosophers typically ask questions that touch on almost every other field of academic inquiry. In fact, one major role of philosophy is to provide the underpinning for just about every other field of study, everything from the rules governing research in that field to its relationship to the other fields of human endeavor. As a result, most universities offer courses in the "philosophy of" other academic disciplines, of interest to both philosophers and students of the respective field. Despite these far-ranging interests, there are some unifying features of philosophical inquiry...


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Talk:Introduction to Philosophy/Authors/MK

Welcome MK, I hope you enjoy your work here as much as I do. I just left you some responses in the staff lounge. BTW, if you sign in with a user account the site tracks your edits for you so you can see which pages have changed, it alerts you when people have left you messages, etc. Plus you can set preferences, and upload images. --Karl Wick

Thanks! I am sure I will enjoy it, though it is likely to take me a very long time to complete my first project as I am working full-time in the IT department at my university, I am teaching philosophy at the same school and I have a computer consulting business of my own. Nonetheless, I support this idea and will contribute what I can as time permits. Thanks so much for your kind assistance. --RMK

If you don't mind, I have been so empetuous to add some text to the empty question: "Why study philosophy?". If you do mind, please change or delete it - but then I'm curious why so... ( NicoBenschop 16jun04)


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Organic Chemistry/Introduction to reactions/Zaitsev's rule

Zaitsev's (sometimes spelled "Saytzeff") rule: In elimination reactions, the major reaction product is the most substituted alkene. The most substituted alkene is also the most stable.

Read about Alexander Mikhailkovich Zaitsev, the chemist on Wikipedia.