The area (in sq. units) of the region described by $A=\left\{(x, y): x^2+y^2 \leq 1 \text { and } y^2 \leq…
- $\left(\frac{\pi}{2}-\frac{2}{3}\right)$
- $\left(\frac{\pi}{2}+\frac{4}{3}\right)$
- $\left(\frac{\pi}{2}-\frac{4}{3}\right)$
- $\left(\frac{\pi}{2}+\frac{2}{3}\right)$
Solution
$\begin{aligned} & A=\left\{(x, y): x^2+y^2 \leq 1 \text { and } y^2 \leq 1-x\right\} \\ & =\text { Area of semicircle }+ \text { Area of the region bounded by parabola and } \\ & \text { y-axis } \\ & =\frac{\pi \times 1^2}{2}+2 \int_0^1 \sqrt{1-x} d x \\ & =\frac{\pi}{2}+2 \times \frac{2}{3}\left[-(1-x)^{3 / 2}\right]_0^1 \\ & =\frac{\pi}{2}+\frac{4}{3}\left[-0^{3 / 2}+1^{3 / 2}\right] \\ & =\frac{\pi}{2}+\frac{4}{3}\end{aligned}$Asked in: MHT CET 2022 (06 Aug Shift 2)