# Favorite Equation?

## What's your favorite chem/physics/math equation?   1 member has voted

1. ### 1. What's your favorite chem/physics/math equation?

• PV=nRT
14
• e=mc^2
25
• F=ma
15
• e^(pi*i) + 1 = 0
22
• Fg = -G(m1m2/r^2)er
7
• integ(uv) = uv - integ(v du)
5
• a^2+b^2=c^2
10
• zeros(ax^2+bx+c) = (-b +- sqrt(b^2-4ac))/(2a)
3
• e=nhv
0
• Other
31

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$[ik,m] = \tfrac{1}{2}(\frac{\partial g_{im}}{\partial x^k}+\frac{\partial g_{km}}{\partial x^i} - \frac{\partial g_{ik}}{\partial x^m})$, and $\{^m_{ik}\} = g^{mn}[ik,n]$. This took quite a while to learn to compose, yes!!! How satisfying to speak the same language. Party at the TOWER.

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• 2 months later...
• Replies 85
• Created

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i like F=ma because it's simple... unlike the others..

btw, i am a newbie here, nice to meet u all in this forum

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cos(pi/5) = ¼ + ¼*√5

I like this one most, because I derived it myself as highschool boy, long before I ever had heard of group theory, Galois theory etc. At school we only had to learn cos(pi), cos(pi/2), cos(pi/3), cos(pi/4) and cos(pi/6) as special values. It was very striking to me that cos(pi/5) also has a special value.

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I like: HIO4 + flat raised base = Periodic Table

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Number of ways to pick k items from n choices. I like it because I solved it myself before I was studying probability, only to learn that Pascal beat me by several hundred years.

$^nC_k = \frac{n!}{(n-k)!k!}$

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• 1 month later...

y=mx+b

slope intercept form of an equation. Don't know why I like it.

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I like

mostly because I haven't got the slightest what it's all about. It has something to do with Yukawa interaction between a scalar and a Majorana field.

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It has something to do with Yukawa interaction between a scalar and a Majorana field.

Marijuana field more like

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I have to say my personal favourite is Newton's second law of motion: F=ma. Why? It's simple, sleak and the only one I can remember without thinking for a second. But of course, the three main kinematic relations:

v=u+at

s=ut+0.5at²

v²=u²+2as

and obviously their angular brothers which I don't know how to write the symbols for on the computer.

Derek.

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• 1 year later...

I voted for this (integ(uv) = uv - integ(v du))one cause in Spanish (I am Spaniard) we memorice it with a funny phrase:

S(uv) = uv-S(v du). S(uv) = Un Viejo-Salido(Viola Dos Universitarias).

And this means: A green old man raped two universitarian girls.

Funny?

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I like Lagrange (and Laplace) transforms, they're pretty cool.

Or this:

$1... (H=\sum_i \Delta_i X_i)$

$2... H=\sum_i (\Delta_i X_i + h_i Z_i) +\sum_{ij} J_ij Z_i Z_j$

$3... H=\sum_i h_i Z_i +\sum_{ij} J_ij Z_i Z_j$

$4... E=\sum_i h_i s_i +\sum_{ij} J_ij s_i s_j$

..which defines a quantum 'process', apparently (and the ordering is crucial). But I only have an idea what it all means (X and Z are the Pauli matrices, at least I know what a matrix is)...

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