Definite Integration Question 483
Question: $ \int_0^{\pi }{x\sin xdx=} $
[SCRA 1980, 91]
Options:
A) $ \pi $
B) 0
C) 1
D) $ {{\pi }^{2}} $
Show Answer
Answer:
Correct Answer: A
Solution:
$ I=\int_0^{\pi }{x\sin xdx=\int_0^{\pi }{(\pi -x)\sin xdx}} $
therefore $ 2I=\pi \int_0^{\pi }{\sin xdx=\pi [-\cos x]_0^{\pi }\Rightarrow I=\pi } $ .