Electronic Journal of Differential Equations, Vol. 2005(2005), No. 138, pp. 1-18. Title: Nonlinear Kirchhoff-Carrier wave equation in a unit membrane with mixed homogeneous boundary conditions Author: Nguyen Thanh Long (Vietnam National Univ., Hochiminh, Vietnam) Abstract: In this paper we consider the nonlinear wave equation problem $$\displaylines{ u_{tt}-B\big(\|u\|_0^2,\|u_{r}\|_0^2\big)(u_{rr}+\frac{1}{r}u_{r}) =f(r,t,u,u_{r}),\quad 00$. Submitted August 3, 2004. Published December 1, 2005. Math Subject Classifications: 35L70, 35Q72. Key Words: Nonlinear wave equation; Galerkin method; quadratic convergence; weighted Sobolev spaces.