Double ultraspherical solution of eigenvalue problems for partial differential equations

Particular spectral method based on an expansion in double ultraspherical polynomials is proposed to solve a number of eigenvalue problems defined by partial differential equations with constant and variable coefficients.We obtain comparable results with those computed by Liu and Oritz [14] by using Tau-Lines method, El-Hawary [8] by using El-Gendi-Lines method, El-Hawary [7] by using double Chebyshev approximation and Brandt et al.[1] by using multigrid method.