hi
i want to know how to compare $\displaystyle span(u) $ and $\displaystyle span(v,w)$ such that $\displaystyle w=2u+v$ and $\displaystyle u$ and $\displaystyle v$ are collinear.
i also want to know how to graph span(u) such that $\displaystyle u $ is in $\displaystyle \mathbb{R}^{2}$