題組內容

2. Let $\underline{x} = \begin{bmatrix} x_1 \\ x_2 \end{bmatrix}$ be a vector in $R^2$ and L: y = mx be a line in $R^2$.

b. (5%) Find the projection matrix P that projects $\underline{x}$ onto the line L, i.e. find P such that $\underline{x}_p = P\underline{x}$.