Maximum Principle for Solution of Biharmonic Equation in The Ball

The intention of this paper is to estimate the biharmonic equation  on a bounded domain  in the space for  with the boundary condition: where we made a function  that equivalent the solution of biharmonic equation:   by using  and applying the principle of the maximum and minimum value, we can estimate the solution of biharmonic equation through the boundary value  : where  is a continuous function ,  Laplace operator ,  biharmonic operator ,  is the boundary of the domain   ,   is the derivative for the outward rhyming on the boundary of ,  , and  is Nabla’s operator.