Definite Integration Question 496

Question: The value of $ \int _{-1}^{1}{\frac{\sin x-x^{2}}{3-|x|}dx} $ is

[Roorkee 1995]

Options:

A) 0

B) $ 2\int_0^{1}{\frac{\sin x}{3-|x|}dx} $

C) $ 2\int_0^{1}{\frac{-x^{2}}{3-|x|}}dx $

D) $ 2\int_0^{1}{\frac{\sin x-x^{2}}{3-|x|}dx} $

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Answer:

Correct Answer: C

Solution:

$ I=\int _{-1}^{1}{\frac{\sin x-x^{2}}{3-|x|}}dx=\int _{-1}^{1}{\frac{\sin x}{3-|x|}}dx-\int _{-1}^{1}{\frac{x^{2}}{3-|x|}}dx $

Here, $ f(x)=\frac{\sin x}{3-|x|} $ is an odd function but $ f(x)=\frac{x^{2}}{3-|x|} $ is an even function
$ \therefore I=-\int _{-1}^{1}{\frac{x^{2}}{3-|x|}}dx=-2\int_0^{1}{\frac{x^{2}}{3-|x|}}dx $

$ =2\int_0^{1}{\frac{-x^{2}}{3-|x|}}dx $ .