function approximations

We present here, three- dimensional Haar wavelet based method for solving well known two- dimensional telegraph equation, by approximating higher order mixed derivatives by a series of higher dimensional Haar wavelet functions, which are integrated subsequently to get wavelet approximation of the solution. Numerical examples have been solved to illustrate the accuracy and efficiency of the proposed Haar wavelet method. High accuracy of the results even in the case of a small number of collocation points have been observed.