clear;clc;
m=[1 2 3];
a=-8;
R=abs(a)^(1/3);
Theta=(angle(a)+2*pi*m)/3;
rrr=R*exp(sqrt(-1)*Theta);
t=0:pi/20:2*pi;
x=R*sin(t);y=R*cos(t);
plot(x,y,'b:'),grid
hold on
plot(rrr(1),'.','MarkerSize',50,'Color','r')
plot(rrr([2 3]),'o','MarkerSize',15,'Color','b')
axis([-3,3,-3,3]),axis square
hold off