Question

Evaluate
$\frac{d}{dt}\underset{0}{\overset{t}{\int }}\cos x^{2}dx$

Answer 1

$f\left(t\right)={\int }_0^t\cos x^{2}dxf\left(x\right)=\cos x^2$

According fundamental theorem

$\frac{df\left(t\right)}{dt}=f\left(t\right)$

$=\cos t^2$