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The area (in sq. units) of the region $\mathrm{S}=\{\mathrm{z} \in \mathrm{C} ;|\mathrm{z}-1| \leq 2 ;(\mathrm{z}+\overline{\mathrm{z}})+\mathrm{i}(\mathrm{z}-\overline{\mathrm{z}}) \leq 2, \operatorname{Im}(\mathrm{z}) \geq 0\}$ is

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  • #12514
    UPLIFTJEE
    Keymaster

    The area (in sq. units) of the region $\mathrm{S}=\{\mathrm{z} \in \mathrm{C} ;|\mathrm{z}-1| \leq 2 ;(\mathrm{z}+\overline{\mathrm{z}})+\mathrm{i}(\mathrm{z}-\overline{\mathrm{z}}) \leq 2, \operatorname{Im}(\mathrm{z}) \geq 0\}$ is [JEE (Main) 4 April 2024 S II]
    (A) $\frac{7 \pi}{3}$
    (B) $\frac{7 \pi}{4}$
    (C) $\frac{17 \pi}{8}$
    (D) $\frac{3 \pi}{2}$

    #12515
    UPLIFTJEE
    Keymaster

    Solution

    According to the question, Put $\mathrm{z}=\mathrm{x}+\mathrm{iy} \Rightarrow(\mathrm{z}+\overline{\mathrm{z}})+\mathrm{i}(\mathrm{z}-\overline{\mathrm{z}}) \leq 2 \Rightarrow 2 \mathrm{x}+\mathrm{i}(2 \mathrm{iy}) \leq 2$

    \[ \begin{aligned} & \Rightarrow \mathrm{x}-\mathrm{y} \leq 1 \\ & |\mathrm{z}-1| \leq 2 \end{aligned} \]

    interior part of circle with centre $(1,0)$ and $\mathrm{r}=2$

    \[ \operatorname{Im}(\mathrm{z}) \geq 0 \Rightarrow \mathrm{y} \geq 0 \]

    Required area = Area of semi-circle-area of sector $\mathrm{A}=\frac{1}{2} \pi(2)^{2}-\frac{\pi^{2}}{2}\left(\frac{\pi}{4}\right)=\frac{3 \pi}{2}$

    #12516
    UPLIFTJEE
    Keymaster

    Answer

    D

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