Z=2-i supra 2+ i. Aflati modulul

Răspuns :

[tex]\text{Mai intai amplificam cu conjugatul.}\\ z=\dfrac{2-i}{2+i}=\dfrac{(2-i)^2}{4+1}=\dfrac{4-4i-1}{5}=\dfrac{3}{5}-\dfrac{4}{5}i\\ |z|=\sqrt{\dfrac{9}{25}+\dfrac{16}{25}}=\sqrt{\dfrac{25}{25}}=1[/tex]
|z1/z2|=|z1|/|z2|=√((2²+(-1)²)/√(2²+1²)=√5/√5=1
as simple as that!!!