1)

The correct evaluation of $\int_{0}^{\pi/2} |\sin^{4}x|dx$ is


A) $\frac{8\pi}{3}$

B) $\frac{2\pi}{3}$

C) $\frac{4\pi}{3}$

D) $\frac{3\pi}{8}$

Answer:

Option D

Explanation:

$\int_{0}^{\pi/2} |\sin^{4}x|dx$ = $\int_{0}^{\pi/2} \sin^{4}xdx$

Applying gamma function,

$2\int_{0}^{\pi/2} \sin^{4}xdx=2\frac{\Gamma(5/2).\Gamma(1/2)}{2.\Gamma(6/2)}=\frac{3\pi}{8}$