hi i write this matlap code but when i plot it i get an empty graph

vt=-7; w=0.47; L=0.025; m=1.22; c0=34.515e-9;k=(w*m*c0/(2*L));

for vg=0:10:40

          Id=k*(vg-vt).^2
  plot(vg,Id,'r');
  hold on;

end

Answer 1

[Walter Roberson]

Change the 'r' to 'r*'

[shaker mahmood]

thank you for your help but why its only show a points while it has to be a curve

[Walter Roberson]

You only ask it to plot one point at a time. MATLAB has no way of knowing that you want the points to be connected. If you want points to be connected in a plot then you need to give plot at least two points, the place to draw from and the place to draw to.

All of which is leading to the fact that you should not be plotting inside the loop. Instead you should be calculating the coordinates and storing them in a vector, and then you can plot the vector after the loop.

Answer 2

[shaker mahmood]

thank you