Determine whether each of the following functions is a solution of Laplace's equation uxx + uyy = 0. (Select all that apply.) u = e^(-x) cosy - e^(-y) cosx u = ln(x^2+y^2) u = x^3 + 3xy^2 u = x^2 - y^2 u = sinxcoshy + cosxsinh u = x^2 + y^2
