Definite Integration Question 93

Question: For $ 0\le x\le \pi , $ the area bounded by $ y=x $ and $ y=x+\sin x, $ is

[Roorkee Qualifying 1998]

Options:

A) 2

B) 4

C) $ 2\pi $

D) $ 4\pi $

Show Answer

Answer:

Correct Answer: A

Solution:

The curves $ y=x $ and $ y=x $ intersect at (0, 0) and $ (\pi ,\pi ) $ .

Hence area bounded by the two curves $ =\int\limits_0^{\pi }{(x+\sin x)dx-\int\limits_0^{\pi }{xdx}=\int\limits_0^{\pi }{\sin xdx}} $

$ =[-\cos x]_0^{\pi }=-\cos \pi +\cos 0=-(-1)+(1)=2 $ .