The Blasius equation is an autonomous, third order, nonlinear differential equation, which results from an appropriate substitution in boundary layer equations. We study in details the concave solutions of initial value problems involving this equation, and apply our results to solve a related boundary value problem

in this paper, we investigate the goursat problem in the class c21(d)cn0 (d  p) c00 (d q)for a third order pseudoparabolic equation. some results are given concerning the existence and uniquenessfor the solution of the suggested problem.