clear all
close all
t=linspace(0,8*pi,100);
x=t.*cos(t);
y=t.*sin(t);
z=t;
plot3(x,y,z)
hold on
x1=5*cos(t);
y1=5*sin(t);
plot3(x1,y1,z)
x2=(8*pi*t-t.^2).*cos(t)/5;
y2=(8*pi*t-t.^2).*sin(t)/5;
plot3(x2,y2,z)

