The area (in sq. units) of the region $S=\{z \in \mathbb{C}:|z-1| \leq 2 ;(z+\bar{z})+i(z-\bar{z}) \leq 2,…
The area (in sq. units) of the region $S=\{z \in \mathbb{C}:|z-1| \leq 2 ;(z+\bar{z})+i(z-\bar{z}) \leq 2, \operatorname{Im}(z) \geq 0\}$ is
- $\frac{7 \pi}{3}$
- $\frac{7 \pi}{4}$
- $\frac{17 \pi}{8}$
- $\frac{3 \pi}{2}$
Solution
Put $z=x+i y$
$|z-1| \leq 2 \Rightarrow(x-1)^2+y^2 \leq 4$ ...(i)
$\Rightarrow x-y \leq 1$ ...(ii)
$\operatorname{Im}(\mathrm{z}) \geq 0 \Rightarrow \mathrm{y} \geq 0$ ...(iii)

$\begin{aligned} & \text { Required area } \\ & =\text { Area of semi-circle }- \text { area of sector A } \\ & \frac{1}{2} \pi(2)^2-\frac{\pi}{2} \\ & =\frac{3 \pi}{2}\end{aligned}$
Asked in: JEE Main 2024 (04 Apr Shift 2)
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