Definite Integration Question 9

Question: The value of $ \int _{-1}^{1}{(\sqrt{1+x+x^{2}}-\sqrt{1-x+x^{2}})dx} $ is

Options:

A) 0

B) 1

C) $ -1 $

D) None of these

Show Answer

Answer:

Correct Answer: A

Solution:

Let $ f(x)=\sqrt{1+x+x^{2}}-\sqrt{1-x+x^{2}} $ .

Then $ f(-x)=\sqrt{1-x+x^{2}}-\sqrt{1+x+x^{2}}=-f(x) $

Hence $ f(x) $ is an odd function and so $ \int _{-1}^{1}{f(x)dx=0} $ .