A flat non conducting sheet lies in the x - y plane the

Question

Compute all parts of given problem:

Problem: A flat non conducting sheet lies in the x - y plane. The only charges in the system are on this sheet. In the half space above the sheet, z > 0, the potential is phi=phi0e-kz coskx, where phi0 and k are constants.

Part I: Verify that phi satisfies Laplace's equation in the space above the sheet.

Part II: What do the electric field lines look like?

Part III: Describe the charge distribution on the sheet?

I am need of complete solution for this problem please help- me out to get right solution.