Provide an Appropriate Response $\mathbf { u }$ Is a Differentiable Function Of

question 95

Essay

Provide an appropriate response.
-Prove that if $\mathbf { u }$ is a differentiable function of $\mathrm { t }$ and $\mathrm { f }$ is a differentiable scalar function of $\mathrm { t }$ , then
$\frac { d } { d t } ( f u ) = \frac { d f } { d t } \mathbf { u } + f \frac { d u } { d t } \text {. }$