|z|=sqrt(2^2+(-2)^2)=sqrt(8)
arg z= φ
tg φ =y/x=-1
φ =-π/4
z=sqrt(8)*(cos(-π/4)+isin(-π/4)
z=sqrt(8)*(cos(π/4)-isin(π/4))
z^5=(sqrt(8))^5*(cos(5*(π/4))-isin(5*(π/4)))
sqrt(8)=sqrt(2^3)=2^(3/2)
(sqrt(8))^5=(2^(3/2))^5=2^(15/2)
z^5=2^(15/2)*(cos(5π/4)-isin(5π/4))
z^5=2^(15/2)(-sqrt(2)/2-i*(-sqrt(2)/2))
z^5=2^(15/2)(-2^(1/2)-i*(-2^(1/2)))
[b]z^5=-128+ 128i[/b]