Favorite Equation?

[Daecon]

*sigh* There's always someone waiting to bring down the tone of the place...

 

;-)

[MetaFrizzics]

[math] 4\pi r^2 = 2(\pi r(2r)) [/math]

 

Surface of a Sphere = Surface of Cylinder of equal radius and height.

AND, any slice of a sphere between two parallel planes has the same area as a cylinder the same height with a radius equal to the original sphere.

 

[ed84c]

Girls=Evil etc etc

 

I like that equation the best

[VikingF]

6: ultraviolet voodoo!

 

 

Not that hard to explain.

 

We know that:

[uv]' = u'v+uv'

 

If we take the integral on both sides, we get:

 

int([uv]')dx = int(u'v)dx + int(uv')dx

(assumes that x is the variable in the equation)

 

int([uv]')dx = uv, so:

uv = int(u'v)dx + int(uv')dx

 

The sollutions are then:

(1): int(u'v)dx = uv - int(uv')dx, and

(2): int(uv')dx = uv - int(u'v)dx

 

Not more woodoo than that.

[TheGeek]

god, as always, e=mc2 gets the votes simply because people recognize it better

 

I do agree with that to some extent. One of the reasons that people recognize it better is because it is a very important equation.

[PhDP]

[math] e^{i\pi} = -1 [/math]

 

...and

 

[math] 1 = \int_{\alpha}^{\rho} e^{-rx}m(x)l(x)dx [/math]

 

It's an equation so simple but so usefull in evolutionary ecology.

[theorein]

What's your favorite equation from chemistry/physics/mathematics?

 

If yours isn't listed' date=' choose other and reply with it![/quote']

 

This equation has the answer to GRAVITY and Cold Fusion

 

theorein

[ecoli]

I'm a fan of Henderson-Hesselbach.

[Severian]

[math]{\cal L} = \bar \psi \left( i \gamma^{\mu} \partial_{\mu} -m \right) \psi - \frac{1}{4} F^{\mu \nu}F_{\mu \nu} [/math]

[bascule]

[math]f_j = \sum_{k=0}^{n-1} x_k e^{-{2\pi i \over n} jk }[/math]

[the tree]

[math]\frac{(U+C+I)(10-S)}{20}\times A\times \frac{1}{1-\sin{\frac{F}{10}}}[/math]

 

Any guesses as to what it is?

[bascule]

I like this one too... beauty in simplicity

 

[math]\phi = {\sqrt{5}+1 \over 2}[/math]

[the tree]

This equation has the answer to GRAVITY and Cold Fusion

Sound's fun, do we get to see it?

[ydoaPs]

This equation has the answer to GRAVITY and Cold Fusion

 

theorein

i don't see it

[ydoaPs]

[math]ln(2)=\sum^{\infty}_{k=1}{\frac{(-1)^{k+1}}{k}}[/math]

 

mercator series when x=1.....lovely expression for ln(2)

[RyanJ]

[math]e^{i\pi} + 1 = 0[/math] wins out for me every time! Simply because it lists so many importannt and intresting things in it

 

[math]E=mc^2[/math] Comes in a close second and any of the others could be third depending on my mood

 

Cheers,

 

Ryan Jones

[uncool]

Typo: Integration by parts is:

integral(u dv) = uv - integral(v du)

 

Personally, I like translation of coordinates with Jacobian...

doubleintegral(F(x,y)dy dx) = doubleintegral(F(x(a,b),y(a,b))J((x,y),(a,b))db da)

=Uncool=

[cosine]

Mine is [math]a + b = b + a[/math]

 

Too often we take commutativity for granted!

[the tree]

Uncool, use LaTeX, it's so much more attractive.

 

[math]\int u\cdot dv = uv - \int v \cdot du[/math]

 

[math]\iint f(x,y)\cdot dy\cdot dx = \iint f\Big(x(a,b),y(a,b)\Big)j\Big((x,y),(a,b)\Big)\cdot db \cdot da[/math]

[Royston]

Well so far for me it's [math]E=mc^2[/math] simple, elegant and holds far reaching implications.

[herpguy]

Mine is a=lw because it helped me get through many years of elementary school.

[deltanova]

v=fw

 

(lol here w= wavelength, dont know how to use latex and cant find the symbol thingie for wavelength.)

 

why? because this is the very first formula i learnt in my physics class! (about 3 weeks ago)

[the tree]

dont know how to use latex and cant find the symbol thingie for wavelength

You mean lambda? That'd be λ. In LaTeX it'd be: [math]v=f\lambda[/math]. (Click on any LaTeX image for teh code).

[deltanova]

Thanks heaps XD

[Norman Albers]

I describe necessary vacuum currents to solve for what's implied when you say 'Gaussian wave packet'. This should be the RHS of the Maxwell current eq: j = (-lambda^2 + rho/U) A . THUS IS THE VACUUM NOT A VACUUM