(Oral Centrale) Soient {A\in{\mathcal M}_{3,2}(\mathbb{R})} et {B\in{\mathcal M}_{2,3}(\mathbb{R})}. On suppose que {AB =\begin{pmatrix}0&-1&-1\\-1&0&-1\\1&1&2\end{pmatrix}}. Calculer {BA}. |
(Oral Centrale) Soient {A\in{\mathcal M}_{3,2}(\mathbb{R})} et {B\in{\mathcal M}_{2,3}(\mathbb{R})}. On suppose que {AB =\begin{pmatrix}0&-1&-1\\-1&0&-1\\1&1&2\end{pmatrix}}. Calculer {BA}. |