\begin{exercice*}
  Soit $\vv{u}$, $\vv{v}$, $\vv{w}$, $\vv{r}$ et $\vv{t}$ des
  vecteurs non nuls.  

  Compléter.
  \begin{enumerate}
  \item
    $\left(\vv{u},\vv{v}\right)+\left(\vv{v},\vv{w}\right)=...$
  \item
    $\left(...,\vv{w}\right)+\left(...,\vv{t}\right)=\left(\vv{v},\vv{t}\right)$
  \item
    $\left(\vv{t},\vv{w}\right)+\left(...,\vv{t}\right)=\left(\vv{v},\vv{w}\right)$
  % \item
  %   $\left(\vv{w},\vv{r}\right)=\left(\vv{w},\vv{t}\right)+\left(...,...\right)$
  \end{enumerate}
\end{exercice*}
\begin{corrige}
  \begin{enumerate}
  \item
    $\left(\vv{u},\vv{v}\right)+\left(\vv{v},\vv{w}\right)=\left(\vv{u},\vv{w}\right)$
  \item
    $\left(\vv{v},\vv{w}\right)+\left(\vv{w},\vv{t}\right)=\left(\vv{v},\vv{t}\right)$
  \item
    $\left(\vv{t},\vv{w}\right)+\left(\vv{v},\vv{t}\right)=\left(\vv{v},\vv{w}\right)$
  % \item
  %   $\left(\vv{w},\vv{r}\right)=\left(\vv{w},\vv{t}\right)+\left(\vv{t},\vv{r}\right)$
\end{enumerate}
\end{corrige}
