Definite Integration Question 225

Question: $ \int_0^{\pi /2}{{{\cos }^{2}}xdx=} $

Options:

A) $ 1-\frac{\pi }{4} $

B) $ 1+\frac{\pi }{4} $

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

D) $ \frac{\pi }{2} $

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Answer:

Correct Answer: C

Solution:

Using gamma function, $ \int_0^{\pi /2}{{{\cos }^{2}}xdx} $ = $ \frac{\Gamma ( \frac{3}{2} )\Gamma ( \frac{1}{2} )}{2\Gamma (2)}=\frac{\frac{1}{2}\Gamma ( \frac{1}{2} )\Gamma ( \frac{1}{2} )}{2.1.\Gamma (1)}=\frac{\pi }{4} $ .