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
  1. $\frac{7 \pi}{3}$
  2. $\frac{7 \pi}{4}$
  3. $\frac{17 \pi}{8}$
  4. $\frac{3 \pi}{2}$

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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