Question: (Partial Derivatives)

Determine for each of the following functions f (x, y) if it is a solution of Laplace’s equation \({{f}_{xx}}+{{f}_{yy}}=0\)

(a) \(f\left( x,y \right)={{e}^{-2y}}\cos \left( 2x \right)\)

(b) \(f\left( x,y \right)=\sin x\cosh y+\cos x\sinh y\)