Answer
$y^{\prime}=x\sinh x$
Work Step by Step
Apply the product rule andTh. 5.18:$\qquad$
$ \displaystyle \frac{d}{dx}[\sinh u]=(\cosh u)u^{\prime}$
$\displaystyle \frac{d}{dx}[\cosh u]=(\sinh u)u^{\prime}$
$y=x\cosh x-\sinh x$
$y^{\prime}=[x(\cosh x)^{\prime}+(x)^{\prime}\cosh x]-(\sinh x)^{\prime}$
$y^{\prime}=[x\sinh x+\cosh x]-\cosh x$
$y^{\prime}=x\sinh x$