A nonlinear parabolic problem is solved by a linear approximation scheme us
ing a nonstandard time discretization with a relaxation function. The relax
ation function is determined by iterations. Optimal rate of convergence is
proved for semi-discretization (in time). Error estimates are obtained for
the full discretization scheme (in time and space). The proposed approximat
ion scheme converges also in the case of degenerate parabolic problems.