1. The problem statement, all variables and given/known data Write an expression for the Dirichlet Green's function of the part of the space bounded by two infinite conducting plates parallel each other and separated by distance of d. Use Image charge method 2. Relevant equations G (at z=0) =0, G (at z=d) =0 I guess 3. The attempt at a solution I am confuse about image charge method. What is the actual principles of this method? On most of problem I ever seen, when we use image method, there is always a point charge in the system, however in this case not. Can anyone help me?