Apply the method of separation of variables to solve the following Dirichlet boundary value problem uxx +uyy = 0, 0

Find the series solution of the Dirichlet problem 2u(r,) = 0; 0 r < 1, , u(1,) = ||( ||), .

) Consider the Dirichlet problem in an annulus in R3, ={(r,) R2; 0 < a

Please don't solve this problem. I posted by mistake.