The value of \( \int_{-1}^{1}\sqrt{|x|-x}\,dx \) is equal to :
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → \( \displaystyle\frac{2\sqrt{2}}{3} \)
Because of the modulus, the integral splits at x = 0.
For \( x\ge 0 \), \( |x|-x=0 \), so the integrand is 0 there.
For \( x\lt 0 \), \( |x|-x=-2x \), so
\( \displaystyle \int_{-1}^{1}\sqrt{|x|-x}\,dx=\int_{-1}^{0}\sqrt{-2x}\,dx \)
Let \( t=-x \):
\( \displaystyle \int_{-1}^{0}\sqrt{-2x}\,dx=\sqrt{2}\int_{0}^{1}t^{1/2}\,dt \)
\( \displaystyle =\sqrt{2}\cdot\frac{2}{3} \)
\( \displaystyle =\frac{2\sqrt{2}}{3} \)