If $\alpha$ is the modulus of $z_1=4+3 i$, then a point that does not lie in the region represented by…

If $\alpha$ is the modulus of $z_1=4+3 i$, then a point that does not lie in the region represented by $\left|z-\overline{z_1}\right| \leq \alpha$ is
  1. $z_1-2 i$
  2. $\mathrm{z}_1$
  3. $2 z_1-7 i$
  4. $3 \mathrm{z}_1-(10+8 \mathrm{i})$

Solution

Given $z_1=4+3 i$ $\Rightarrow\left|z_1\right|=\alpha=\sqrt{4^2+3^2}=5$ Now, $|z-\overline{4+3 i}| \leq 5 \Rightarrow|z-(4-3 i)| \leq 5$ If we put $\mathrm{z}=4+3 \mathrm{i}$ $|4+3 i-4+3 i|=|6 i| \leq 5$ so $z_1$ is not lies in $\left|z-z_1\right| \leq \alpha$

Asked in: AP EAMCET 2023 (16 May Shift 2)

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