# Solving Laplace Equation having boundary conditions

#### Vinod

Hello,

Please watch this video [video]https://youtu.be/_cPU-nf9owk[/video] and tell me whether $A)C_{n,m}=\frac {16V_0}{\pi^2 mn\cosh{\bigg(\sqrt{(\frac{n\pi}{a})^2+ (\frac{n\pi}{a})^2}}\bigg)}$ or $B)C_{n,m}=\frac {16V_0}{\pi^2 mn\cosh{\bigg(\sqrt{(\frac{n\pi}{a})^2+ (\frac{n\pi}{a})^2}}\frac{a}{2}\bigg)}$ Which is correct A) or B)?

Last edited:

MHF Helper
1 person

#### Vinod

You are kidding, right?
Hello,

Notice the argument of $\cosh$. The Math professor in the video put $\beta= \sqrt{(\frac{n\pi}{a})^2+(\frac{m\pi}{a})^2}y$ where $y=\frac{\pm a}{2}$ But i think math professor in the video forgot to put y in the argument of $\cosh$ while calculating $C_{n,m}$. Also math professor didn't comment at $V=0$ at the centre of cube. Is $E=0$ there?