Let \vec{v} = \left [ \begin{matrix} 2 \\ 1 \\ 1 \end{matrix} \right ] and \vec{u} = \left [ \begin{matrix} 1 \\ 5 \\ 1 \end{matrix} \right ]. Determine proj_{\vec{v} }(\vec{u} ) and perp_{\vec{v} }(\vec{u} ).
Let \vec{v} = \left [ \begin{matrix} 2 \\ 1 \\ 1 \end{matrix} \right ] and \vec{u} = \left [ \begin{matrix} 1 \\ 5 \\ 1 \end{matrix} \right ]. Determine proj_{\vec{v} }(\vec{u} ) and perp_{\vec{v} }(\vec{u} ).
perp_{\vec{v} }(\vec{u} ) = \vec{u} – proj_{\vec{v} }(\vec{u} ) = \left [ \begin{matrix} 1 \\ 5 \\ 1 \end{matrix} \right ] – \left [ \begin{matrix} 8/3 \\ 4/3 \\ 4/3 \end{matrix} \right ] = \left [ \begin{matrix} -5/3 \\ 11/3 \\ -1/3 \end{matrix} \right ]