# Partial derivative of matrix * constant vector wrt a vector

Is there an identity for simplifying partial derivatives of the form: $\frac{\partial A(\bf{x})\bf{b}}{\partial\bf{x}}$ ?

A is a square matrix that is a function of x, and b is a constant vector.

I can certainly work out the solution to my specific problem, but was wondering if there was a general rule for doing this.

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