sqrt(4-3i)
z=4-3i x=4 y=-3 |z|=sqrt(x^2+y^2)=sqrt(4^2+(-3)^2)=sqrt(25)=5 arg z= phi tg phi=y/x=-3/4 phi=arctg(-3/4) sqrt(z)=(5*cos(phi+2Pik)+isin(phi+2Pik))^(1/2)= =sqrt(5)*(cos(phi+2Pik)/2)+isin(phi+2Pik)/2)), k ∈ Z phi=arctg(-3/4)