The area of the region described by $\left\{(x, y) / x^2+y^2 \leq 1\right.$ and $\left.y^2 \leq 1-x\right\}$…
- $\frac{\pi}{2}-\frac{2}{3}$
- $\frac{\pi}{2}+\frac{2}{3}$
- $\frac{\pi}{2}+\frac{4}{3}$
- $\frac{\pi}{2}-\frac{4}{3}$
Solution

Required area $\begin{aligned} & A=2\left[\int_{-1}^0 \sqrt{1-x} d x+\int_0^1 \sqrt{1-x} d x\right] \\ & =2\left[\frac{x}{2} \sqrt{1-x^2}+\frac{1}{2} \sin ^{-1} x\right]_{-1}^0+2\left[\frac{-2}{3}(1-x)^{\frac{3}{2}}\right]_0^1 \\ & =\frac{\pi}{2}+\frac{4}{3} \end{aligned}$
Asked in: AP EAMCET 2015