Question

$z^{8} + z^{4} -2=0$ ajutatima sa calculez in C ecutia sub forma trigonometrica

Answer 1

$z^{4}$ = t ( prin notatie) ⇒$t^{2}$+t-2=0⇒t=2 sau t=-1 
$z^{4}$=2⇒z=$\sqrt[4]{2}$
sau
$z^{4}$=-1⇒z=i