Derivative of a nonsingular matrix

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$$\frac{d}{dt} A^{-1}(t) = -A^{-1}(t) (\frac{d}{dt} A(t) ) A^{-1}(t) $$

A(t) is a matrix.

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Differentiate with respect to $t$ both sides of the equation $$ A(t) [A(t)]^{-1} = I, $$ getting (via the product rule) $$ A(t) \frac{d}{dt} [A(t)]^{-1} + \Bigl(\frac{d}{dt} A(t)\Bigr) [A(t)]^{-1} = 0. $$ Now multiply both sides of the equation above by $[A(t)]^{-1}$ on the left, getting $$ \frac{d}{dt} [A(t)]^{-1} = - [A(t)]^{-1}\Bigl(\frac{d}{dt} A(t)\Bigr) [A(t)]^{-1}. $$