Hello,

Please watch this video https://youtu.be/_cPU-nf9owk 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)?