If u=<0,1> and v=<e,pi> are 2d vectors, then how do I evaluate the cross product u X v?
For 2d vectors the cross product is a determinant.
If $\displaystyle u=<u_x,u_y>~\&~v=<v_x,v_y>$ then $\displaystyle
u \times v = \left| {\begin{array}{rr}
{u_x } & {u_y } \\
{v_x } & {v_y } \\