Question Number 149142 by mathdanisur last updated on 03/Aug/21
$${if}\:\:\:{z}\:+\:\mid{z}\mid\:=\:\mathrm{1}\:+\:\sqrt{\mathrm{3}}\:\boldsymbol{{i}} \\ $$$${find}\:\:\:\boldsymbol{\varphi}\:=\:? \\ $$
Answered by liberty last updated on 03/Aug/21
$$\mathrm{z}=\mathrm{a}+\mathrm{b}{i} \\ $$$$\mid\mathrm{z}\mid=\sqrt{\mathrm{a}^{\mathrm{2}} +\mathrm{b}^{\mathrm{2}} } \\ $$$$\Rightarrow\mathrm{a}+\mathrm{b}{i}+\sqrt{{a}^{\mathrm{2}} +{b}^{\mathrm{2}} }\:=\:\mathrm{1}+\sqrt{\mathrm{3}}\:{i} \\ $$$$\begin{cases}{{b}=\sqrt{\mathrm{3}}}\\{{a}+\sqrt{{a}^{\mathrm{2}} +\mathrm{3}}\:=\mathrm{1}\:\Rightarrow\sqrt{\mathrm{a}^{\mathrm{2}} +\mathrm{3}}\:=\mathrm{1}ā\mathrm{a}}\end{cases} \\ $$$$\Rightarrow\mathrm{a}^{\mathrm{2}} +\mathrm{3}=\mathrm{a}^{\mathrm{2}} ā\mathrm{2a}+\mathrm{1} \\ $$$$\Rightarrow\mathrm{a}=ā\mathrm{1}\:\mathrm{then}\:\mathrm{z}=ā\mathrm{1}+\sqrt{\mathrm{3}}\:{i} \\ $$$$\mathrm{tan}\:\varphi=\frac{\sqrt{\mathrm{3}}}{ā\mathrm{1}}=ā\sqrt{\mathrm{3}}\: \\ $$$$\varphi=ā\frac{\pi}{\mathrm{3}} \\ $$
Commented by mathdanisur last updated on 03/Aug/21
$${Cool},\:{Thank}\:{You}\:{Ser} \\ $$