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**ganesh****Moderator**- Registered: 2005-06-28
- Posts: 22,081

What is mathematics without formulae? Wouldn't it be nice and useful to have a separate page for formulae alone in the website?

It is no good to try to stop knowledge from going forward. Ignorance is never better than knowledge - Enrico Fermi.

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.

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**ryos****Member**- Registered: 2005-08-04
- Posts: 394

Page? As in only one? That'd take quite a while to load...

I've wished at times for well-indexed books of formulae. Not books that explain them (I have those), but a quick reference so I can look up stuff I need without having to hunt about for them. I'm sure someone's written one...

El que pega primero pega dos veces.

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**ganesh****Moderator**- Registered: 2005-06-28
- Posts: 22,081

There is this website where formulae are given by topic. You can try it, ryos!

It is no good to try to stop knowledge from going forward. Ignorance is never better than knowledge - Enrico Fermi.

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.

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**MathsIsFun****Administrator**- Registered: 2005-01-21
- Posts: 7,632

It certainly would be nice to have. Look up all the trig identities in one spot. Or lists of integrals, etc. ... let's explore the idea more!

Would we have categories? If so, which? Make it searchable with keywords? How?

"The physicists defer only to mathematicians, and the mathematicians defer only to God ..." - Leon M. Lederman

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**ganesh****Moderator**- Registered: 2005-06-28
- Posts: 22,081

Yes, the page can list formula category-wise.

1. Algebra :- Opeartions of integers, rational numbers, and laws of exponents, Quadratic and Quartic equations, Identities, Binomial theorem.

2. Trignometry

3. Plane and Solid Geometry.

4. Coordinate Geometry.

5. Combinatorics.

6. Calculus.

7. Statistics and Prabibility.

8. Logarithms.

9. Vectors.

10. Complex numbers.

I volunteer to contribute! This time I really mean it!

It is no good to try to stop knowledge from going forward. Ignorance is never better than knowledge - Enrico Fermi.

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.

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**Ricky****Moderator**- Registered: 2005-12-04
- Posts: 3,791

I say we just use this post, everyone can donate whatever formulas they know. Just put a number next to which kind of formula it is. For example:

2. sin²θ + cos²θ = 1

"In the real world, this would be a problem. But in mathematics, we can just define a place where this problem doesn't exist. So we'll go ahead and do that now..."

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**ganesh****Moderator**- Registered: 2005-06-28
- Posts: 22,081

Ricky,thats a good suggestion! I feel the posts should also contain the name of the topic apart from the serial number, to help in seggregating. If there's any addition to the topic, the original post number may be mentioned. I shall start.

I. Arithmetic Progressions.

An Arithmetic Progression (AP) is a series in which the succesive terms have a common difference. The terms of an AP either increase or decrease progressively. For example,

1, 3, 5,7, 9, 11,....

10, 9, 8, 7,6, 5, .....

14.5, 21, 27.5, 34, 40.5 .....

11/3, 13/3, 15/3, 17/3, 19/3......

-5, -8,-11, -14, -17, -20 ......

Let the first term of the AP be a and the common difference, that is

the difference between any two succesive terms be d.

The nth term, tn is given by

tn= a + (n-1)d.

The sum of n terms of an AP, Sn is given by the formula

Sn = n/2[2a+(n-1)d] or n/2(a+l) where l is the last term (nth term in this case) of the AP.

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.

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**Ricky****Moderator**- Registered: 2005-12-04
- Posts: 3,791

Let's get this ball rolling people! I know yall know some formulas.

6. Calculus

Mass of a plate:

Movement around the x-axis:

Movement around the y-axis:

Center of mass on the x axis:

Center of mass on the y axis:

*Last edited by Ricky (2006-03-27 08:32:32)*

"In the real world, this would be a problem. But in mathematics, we can just define a place where this problem doesn't exist. So we'll go ahead and do that now..."

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**MathsIsFun****Administrator**- Registered: 2005-01-21
- Posts: 7,632

Good ones Ricky.

Now, my mind is still circling around this subject. Here are two possibilities:

A: A separate database. We could have a field for typing in the LaTeX, a category, sub-category, decription and author(username).

B. Part of the forum. We could have a sub-forum organised like Ganesh's Puzzles. In other words, create a topic "Calculus Formulae", and then add our posts there (We would want to keep the area "on topic" which means no "hey, nice one!" comments, just formulae and their descriptions, usage, etc)

Oh, and the plural of "formula" may correctly be "formulae", but "formulas" is used more commonly according to GoogleFight: http://googlefight.com/index.php?lang=e … 2=formulas

"The physicists defer only to mathematicians, and the mathematicians defer only to God ..." - Leon M. Lederman

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**ganesh****Moderator**- Registered: 2005-06-28
- Posts: 22,081

Thats a good idea. Yes, no posts like 'Good ones', 'Thank you', 'These helped me so much' etc. Only formulae....with the names of the topics...

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.

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**Ricky****Moderator**- Registered: 2005-12-04
- Posts: 3,791

MathIsFun, you could have a heavily moderated section. Basically, have the opening post contain a list of formulas, and then when people post after it, add it to the OP and then delete their post.

"In the real world, this would be a problem. But in mathematics, we can just define a place where this problem doesn't exist. So we'll go ahead and do that now..."

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**MathsIsFun****Administrator**- Registered: 2005-01-21
- Posts: 7,632

I guess it depends on how big this will get ...

If we are going to have thousands of formulae, then I could create a whole Category (the forum currently has 4 categories: "Learning About Maths", "Fun Stuff", "Teaching Maths" and "Maths Is Fun - The Website")

Then we could have sub-forums under that called "Calculus", "Algebra", etc. This would allow individual topics under Calculus, such as "Basic Integration", or Algebra such as "Laws of Exponents".

This would allow more scope for *some* discussion about a formula, such as definitions, usage, etc.

So I guess the question is: Which alternative?

1. One Sub-Forum called "Formulas" with Topics like "Calculus", "Algebra", etc, OR

2. A Category called "Formulas" with several Sub-Forums like "Calculus", "Algebra", and Topics like "Basic Integration", "Laws of Exponents", etc.

"The physicists defer only to mathematicians, and the mathematicians defer only to God ..." - Leon M. Lederman

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**ganesh****Moderator**- Registered: 2005-06-28
- Posts: 22,081

I vote for the first! That would be more convenient of the two!

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.

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**Ricky****Moderator**- Registered: 2005-12-04
- Posts: 3,791

All those in favor of 1, type aye.

Aye.

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**mathsyperson****Moderator**- Registered: 2005-06-22
- Posts: 4,900

Aye aye.

Why did the vector cross the road?

It wanted to be normal.

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**Ricky****Moderator**- Registered: 2005-12-04
- Posts: 3,791

To the plank with ye for voting twice.

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**ryos****Member**- Registered: 2005-08-04
- Posts: 394

Shiver me timbers! One it be. Aye!

El que pega primero pega dos veces.

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**MathsIsFun****Administrator**- Registered: 2005-01-21
- Posts: 7,632

Prepare to set sail then, me lubberlies!

If it not be to yer sattersfaction, then be not afraid to speak yer mind.

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**justlookingforthemoment****Moderator**- Registered: 2005-05-26
- Posts: 2,161

Aye. Squawk! The parrot agrees. 'Tis jolly good.

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**ganesh****Moderator**- Registered: 2005-06-28
- Posts: 22,081

As I always say, I shall start contributing from this weekend!

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.

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