your favorite math equation/geometric property

I think mine is fairly obvious and simple. it helps me to remember the expansions of both cos and sin as well as the expanision for e^x.as if i needed to know any of the three. it as goes hand in hand with e to the i pi plus one equal zero, the five most important numbers in math. awsome.

My favorite is i squared equals minus one. Go figure. If that doesn't prove the existence of God, then I don't know what does. Inexplicable to the core.

My favorite is

1 / 3 = 0.33333333333.... x 3 = 0.999999999....

Therefore, 1 does not equal 1.

I like e^i(pi) + 1 = 0, but my favourite has got to be c=2(pi)r.

The equation for the circumference of a circle introduces pi, the number that crops up in everything mathematicians and physicists do, for the very first time.

Oh and sorry Icarus Rising but i^2=-1 is by no means proof of god. i is a human artifact used by mathematicians to model a property of numbers that is hard for us to conceptulise. Its simply the way numbers work, just as 1+1=2 and x/1=x.

I like 1337

Only kidding. I'm a big fan of the Fibonacci sequence. There are so many things in nature that relate to the number pattern that it boggles the mind.

(0 if n=0;
F(n):=(1 if n=1;
(F(n-1)+F(n-2) if n>1.

I like the very simple but extrememly powerful Pythagorean Theorem:

a² + b² = c²

...which states that the square of the hypotenuse of a right triangle is equal to the sum of the squares of the other two sides.

I spent many years as a carpenter and used this or a variation based on it almost every day.

And God isn't? Btw, it was an if-then proposition.

Then I don't know what is.

If you don't want proof of God, you won't find it.

O come on! It has to be the Bekenstein-Hawking Formula. I'm constantly needing to calculate the gravitational pull near black holes.

image source: http://scienceworld.wolfram.com/physics/bimg59.gif


Just kidding. My favorite formula isn't a real forumla. It's FOIL (First Outer Inner Last) I would have never learned to multiply binomials without this nifty little method to constantly remind me how it's done.


EDIT: I should also mention the Quadratic Formula. It's handy too
image source: http://www.freemathhelp.com/images/math/quadratic.png



[edit on 17-2-2007 by dbates]

Throughout my studies of physics and mathematics, and all the courses I've taken in both subjects, I'd have to say the most beautiful equation is e^i(pi) + 1 = 0. Richard Feynman also thought the same.

I like the recursive Gamma function, given by:

'T^r with Z=n sequencing as a sub-note.

It's quite handy when dealing with phenominal numbers: i.e., chain reactions, astronomical phenomenon, why some people sit at red lights when they're green, etc.

In physics, the best ones are the E&M and gravitational field equations in Einsteinan tensor form.

That's by far my favorite.

It does reveal a very mystical underpinning to the universe IMHO.

Exactly as I remember it.

Burnt into memory 30 years ago by my brother in law, I've never used it in anger.

You stole my thunder dbates..........well done...

Euler's identity is a really good trigonometric identity. e^x = cos x + i sin x

Some of the 'series' equations are pretty cool, too, like the sum of 1/x! = e, for all integer x. There is also one for pi, but I forget exactly how it goes. I think there was a 4 and a bunch of stuff square rooted...

I also like lim x->infinity (1 + 1/x)^(1/x) = e (I think I put that down right, I hope...)

My favourite, however, is...

It is well known that TIME = MONEY
And that MONEY is the root of all evil. MONEY = EVIL^0.5
GIRLS require TIME and MONEY. GIRLS = TIME * MONEY
GIRLS = TIME * MONEY = MONEY^2 = (EVIL^0.5)^2 = EVIL
GIRLS = EVIL
(yeah, engineers are geeks...)

[edit on 17-2-2007 by DragonsDemesne]
(edits to fix very strange formatting problem with one of my formula)

[edit on 17-2-2007 by DragonsDemesne]

Yes indeed. Nature and the universe don't need math and numbers at all, its a human concept / tool to help our feeble minds. Mine being amongst the most feeble.

Favorite eq? Mmm as my background is engineering a nice and simple V=IR and its derivatives. Got us to electronics and no doubt eventually armageddon

The Caley-Hamilton theorem. Suffice to say it is an elegant solution to solving matrices and differential equations.

Here's an old Calculus joke equation:

image source: http://www.pegasuspublishing.com/xcart/files/pics/russ/ias004-sex=fun.jpg

My favorite is the 47th problem of Euclid.



The simple A^2 + B^2 = C^2

The ancients believed that it could be used for squaring the circle. Ancient measure systems were based on the ratios of the 5/12/13 and especially the 3/4/5 triangle. The latter was believed to have esoteric significance.

I've always loved the simplistic 1 + 1 = 10.

Although not possessing a strong math background (history major), having a nice √-1 = i written on the white board in my office was more of a joke to make it look like I was doing high level mathematics.

I went to school with and now work with with a ton of engineers. I did run across this from a fw: e-mail recently.

image source: http://www.brinkleys.org/users/tsl/Files/Engineering_Check_sm.jpg


I'll have to add to my signature and white board chiS2000's 1 does not equal 1.

O yeah! There are 10 kinds of people in the world. Those that understand binary and those that don't.