“…Because of the application of the mixed equations in physical problems, which are based on the time independent and Helmholtz equation, several articles have been studied the solution of mixed problem which has a dual equations [9,6,4,3,5,8,7], [16], [15]. For instance, in this article, we consider a mixed problem of solid cylindrical with an infinite height and given radius R. In particular, inside the disk 0 < r < r 0 , the boundary conditions on the surface of cylindrical and outside the disk r 0 < r < R are given, and of first kind and second kind respectively, or vis versa.…”