Question Number 146702 by faysal last updated on 13/Nov/23
Answered by Olaf_Thorendsen last updated on 15/Jul/21
$$ \\ $$$${ne}^{{i}\theta} \:=\:\frac{\mathrm{3}+\mathrm{3}{i}}{\mathrm{2}+\mathrm{3}{i}}+\frac{\mathrm{1}+\mathrm{5}{i}}{\mathrm{1}−\mathrm{2}{i}} \\ $$$${ne}^{{i}\theta} \:=\:\frac{\mathrm{3}\left(\mathrm{1}+{i}\right)\left(\mathrm{2}−\mathrm{3}{i}\right)}{\left(\mathrm{2}+\mathrm{3}{i}\right)\left(\mathrm{2}−\mathrm{3}{i}\right)}+\frac{\left(\mathrm{1}+\mathrm{5}{i}\right)\left(\mathrm{1}+\mathrm{2}{i}\right)}{\left(\mathrm{1}−\mathrm{2}{i}\right)\left(\mathrm{1}+\mathrm{2}{i}\right)} \\ $$$${ne}^{{i}\theta} \:=\:\frac{\mathrm{3}\left(\mathrm{5}−{i}\right)}{\mathrm{13}}+\frac{\left(−\mathrm{9}+\mathrm{7}{i}\right)}{\mathrm{5}} \\ $$$${ne}^{{i}\theta} \:=\:\frac{\mathrm{15}\left(\mathrm{5}−{i}\right)}{\mathrm{65}}+\frac{\mathrm{13}\left(−\mathrm{9}+\mathrm{7}{i}\right)}{\mathrm{65}} \\ $$$${ne}^{{i}\theta} \:=\:\frac{\mathrm{75}−\mathrm{15}{i}}{\mathrm{65}}+\frac{−\mathrm{117}+\mathrm{91}{i}}{\mathrm{65}} \\ $$$${ne}^{{i}\theta} \:=\:\frac{−\mathrm{42}+\mathrm{76}{i}}{\mathrm{65}} \\ $$$${n}\:=\:\mid\frac{−\mathrm{42}+\mathrm{76}{i}}{\mathrm{65}}\mid\:=\:\frac{\sqrt{\mathrm{42}^{\mathrm{2}} +\mathrm{76}^{\mathrm{2}} }}{\mathrm{65}}\:=\:\frac{\mathrm{2}\sqrt{\mathrm{1885}}}{\mathrm{65}} \\ $$$$\theta\:=\:\mathrm{arg}\left(\frac{−\mathrm{42}+\mathrm{76}{i}}{\mathrm{65}}\right)\:=\:\mathrm{arctan}\left(\frac{\mathrm{76}}{−\mathrm{42}}\right)\:=\:−\mathrm{arctan}\left(\frac{\mathrm{38}}{\mathrm{21}}\right) \\ $$