Select the correct statement about the mathematical character of the Navier-Stokes equation and the boundary layer x-momentum equation. 1) Both the Navier-Stokes equation and the boundary layer x-momentum equation are elliptic. 2) Both the Navier-Stokes equation and the boundary layer x-momentum equation are linear. 3) Both the Navier-Stokes equation and the boundary layer x-momentum equation are parabolic. 4) The Navier-Stokes equation is elliptic, and the boundary layer x-momentum equation is parabolic. 5) The Navier-Stokes equation is parabolic, and the boundary layer x-momentum equation is elliptic.
