Answer
$2^{x^{2}}\cdot x\cdot \ln 2$
Work Step by Step
$\quad$
$\displaystyle \frac{d}{dx}[b^{u}]=b^{u}\ln b\cdot\frac{du}{dx}$
$b=2$
$u(x)=x^{2}-1\displaystyle \qquad \frac{du}{dx}=2x$
$\displaystyle \frac{d}{dx}[b^{x^{2}-1}]=2^{x^{2}-1}\ln 2\cdot 2x$
$=2^{x^{2}-1+1}\cdot x\cdot\ln 2=2^{x^{2}}x\ln 2$