Definite Integration Question 311

Question: The area of the region bounded by the curve $ y=x|x| $ , x-axis and the ordinates $ x=1,x=-1 $ is given by

[Pb. CET 2004]

Options:

A) Zero

B) $ \frac{1}{3} $

C) $ \frac{2}{3} $

D) 1

Show Answer

Answer:

Correct Answer: C

Solution:

Required area $ =\int _{-1}^{1}{x|x|dx} $

$ =\int _{-1}^{0}{-x^{2}dx+\int_0^{1}{x^{2}dx}} $

= $ ( \frac{-x^{3}}{3} ) _{-1}^{0} $

$ +( \frac{x^{3}}{3} )_0^{1} $

$ =| \frac{-1}{3} |+| \frac{1}{3} |=\frac{2}{3} $ .