M1 Mathematics, 2011-2012
MM26E Numerical Approximation of PDEs

Hervé Le Dret

$P_1$-Lagrange approximation

The hat-functions of $P_1$-Lagrange approximation on a triangular mesh.



A hat-function corresponding to an internal node




The same seen from the top




A hat-function corresponding to a boundary node


Here is the $P_1$-interpolate of the function $(x_1,x_2)\mapsto \sin x_1\sin x_2$ on a triangular mesh on a square