Definite Integration Question 260

Question: $ \int_0^{\pi }{{{\sin }^{5}}( \frac{x}{2} )dx} $ equals

[Kurukshetra CEE 1996]

Options:

A) $ \frac{16}{15} $

B) $ \frac{32}{15} $

C) $ \frac{8}{15} $

D) $ \frac{5}{6} $

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Answer:

Correct Answer: A

Solution:

$ \int_0^{\pi }{{{\sin }^{5}}\frac{2}{x}dx=2\int_0^{\pi /2}{{{\sin }^{5}}tdt=2.\frac{\Gamma \frac{6}{2}.\Gamma \frac{1}{2}}{2\Gamma \frac{7}{2}}=\frac{16}{15}}} $ .