If $\mathrm{Z}=x+i y$ is a complex number, then the number of distinct solution of the equation…

If $\mathrm{Z}=x+i y$ is a complex number, then the number of distinct solution of the equation $z^3+\bar{z}=0$ is
  1. $1$
  2. $3$
  3. Infinite
  4. $5$

Solution

Given, $z^3+\bar{z}=0$, where $z=x+i y$ is a complex number $\begin{aligned} & \Rightarrow z^3=-\bar{z} \Rightarrow\left|z^3\right|=|-\bar{z}| \Rightarrow|z|^3=|z| \\ & \Rightarrow|z|^3-|z|=0 \Rightarrow|z|\left(|z|^2-1\right)=0\end{aligned}$ $\begin{aligned} & \Rightarrow|z|=0 \text { or }|z|^2=1 \Rightarrow z \bar{z}=1 \Rightarrow \bar{z}=\frac{1}{z} \\ & \because z=0 \text { or } z^3+\frac{1}{z}=0 \Rightarrow z=0 \text { or } z^4+1=0\end{aligned}$ So, total number of distinct solution of given equation is 5 .

Asked in: AP EAMCET 2024 (18 May Shift 1)

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