Got some problems when trying to plot with a shifting angle in 2D Plotting ?

when i try to plot from (0,0) it becomes great as the below Pic :

The Codes Are :-

hold on;grid;
ang=30;
theta=0;
for i=0:(360/ang)
xl=[0 15*cos(theta*pi/180)];
yl=[0 15*sin(theta*pi/180)];
plot(xl,yl,'-r')
theta=(i+1)*ang;
end

But when i try to change the Co-ordinates it becomes like this :-

The Codes As Below :-

hold on;grid;
ang=30;
theta=0;
for i=0:(360/ang)
xl=[5 20*cos(theta*pi/180)];
yl=[5 20*sin(theta*pi/180)];
plot(xl,yl,'-r')
theta=(i+1)*ang;
end

Thanks & Sorry for long words :D

[Jan]

You show us the code and the output, but do not explain, what the actual problem is. Do you expect the graphics to be symmetrical?

Answer 1

[Jan]

The posted code moves the start points from (0,0) to (5,5) and the end points of each line are located on the circle around (0,0) with radius 20. I guess that you want a circle around (5,5) with radius 15:

hold on;grid;
ang=30;
theta=0;
for i=0:(360/ang)
  xl = [5, 5 + 15*cos(theta*pi/180)];
  yl = [5, 5 + 15*sin(theta*pi/180)];
  plot(xl,yl,'-r')
  theta = (i+1)*ang;
end

Answer 2

[Haytham Mohamed]

thanks alot Jan Simon it works