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 $R^2$.

a. (5%) Find the orthogonal projection of $\underline{x}$ onto the line L, i.e. find the vector $\underline{x}_p$ as shown in the figure below.