\color{rgb(0,0,0)}\vec{u}\left( \begin{array}{c}
1
\\ \sqrt{2}
\\ -1
\end{array} \right)
\text{ et }\vec{v}\left( \begin{array}{c}
0
\\ 2\sqrt{2}
\\ 1
\end{array} \right)
$$\color{rgb(0,0,255)}\Rightarrow \left||\vec{u}\right||=?$$
$$\color{rgb(0,0,255)}\Rightarrow \left||\vec{v}\right||=?$$
$$\color{rgb(0,0,255)}\Rightarrow \vec{u}.\vec{v}=?$$
$$\color{rgb(0,0,255)}\Rightarrow \theta=?$$