Definite Integration Question 64

Question: $ \int _{0}^{\pi }{{e^{{{\sin }^{2}}x}}{{\cos }^{3}}xdx} $ is equals to

[MP PET 2002]

Options:

A) $ -1 $

B) 0

C) 1

D) $ \pi $

Show Answer

Answer:

Correct Answer: B

Solution:

$ I=\int_0^{\pi }{{e^{{{\sin }^{2}}x}}{{\cos }^{3}}xdx} $

$ \Rightarrow I=\int_0^{\pi }{{e^{{{\sin }^{2}}(\pi -x)}}{{\cos }^{3}}(\pi -x)}dx $ ……(i)
$ \Rightarrow I=-\int_0^{\pi }{{e^{{{\sin }^{2}}x}}{{\cos }^{3}}xdx} $ …..(ii)

Adding (i) and (ii), we get $ 2I=0 $

therefore $ I=0 $ .