Definite-Integration Question 507

Question: The correct evaluation of $ \int_0^{\pi }{| ,{{\sin }^{4}}x, |,dx} $ is

[MP PET 1993]

Options:

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

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

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

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

Show Answer

Answer:

Correct Answer: D

Solution:

$ \int_0^{\pi }{| {{\sin }^{4}}x |dx=2\int_0^{\pi /2}{{{\sin }^{4}}x,dx}} $ Applying gamma function, $ 2\int_0^{\pi /2}{{{\sin }^{4}}x,dx}=2\frac{\Gamma (5/2).\Gamma (1/2)}{2.\Gamma (6/2)}=\frac{3\pi }{8} $ .