# Two-dimensional Shape Functions

From KratosWiki

Shape functions are selected to fit as exact as possible the Finite Element Solution. If this solution is a combination of polynomial functions of n^{th} order, these functions should include a complete polynomial of equal order.

That is, a complete polynomial of n^{th} order can be written as:

with *p* = *f**r**a**c*(*n* + 1)(*n* + 2)2

can only fit polynomial functions of p^{th} order if they content a polynomial function

for any polynomial function of pth order it is enough to use p-1 integration points.