Answer
$\dfrac{3}{2}$
Work Step by Step
Re-arrange the given integral as follows:
$\int_{-1}^{2} y dy\int_{0}^{\pi/2} \sin x dx=\dfrac{y^2}{2}]_{-1}^{2} [-\cos x]_{0}^{\pi/2} $
This implies that
$(\dfrac{4}{2}-\dfrac{1}{2})(0-(-1))=\dfrac{3}{2}$
