  We revise the finite element formulation for Lagrange, Raviart- Thomas, and
Taylor-Hood finite element spaces. We solve Laplace equation in first and
second order formulation, and compare the solutions obtained with Lagrange and
Raviart-Thomas finite element spaces by changing the order of the shape
functions and the refinement level of the mesh. Finally, we solve Navier-Stokes
equations in a two dimensional domain, where the solution is a steady state,
and in a three dimensional domain, where the system presents a turbulent
behaviour. All numerical experiments are computed using MFEM library, which is
also studied.
