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Soient \(A = \begin{pmatrix} 1 &\frac12 &\frac13 \cr \frac12 &\frac13 &\frac14 \cr \frac13 &\frac14 &\frac15 \cr \end{pmatrix}\) et \(B = \begin{pmatrix} 1\phantom{.00} &0.5\phantom{0} &0.33 \cr 0.5\phantom{0} &0.33 &0.25 \cr 0.33 &0.25 &0.20 \cr \end{pmatrix}\). Calculer \(A^{-1}\) et \(B^{-1}\).