MATLAB: Plotting results of for loop on one graph

Question

Hi, I am relatively unexperienced with MATLAB, so bear with me! I created a for loop where two of the values in my matrix are functions of r, and then further operations are performed with each iteration of the matrix. The values are generated but then when I try to graph them, I get either an error or no graph. Here's my code:

for r=0:0.001:1.1;

M=[-1*(r.^2)+1.3 -0.3;-0.3, -0.3*(r.^2)+0.3];

f=[1;0];

z_1=M\f;

plot(r,z_1)

end

Thank you in advance!

**As an added comment, if I try to express z_1 as z_1(r), or do this operation without the for loop, I get the error "Subscript indices must either be real positive integers or logicals" and I also don't know how to fix that…

Answer 1

Replace your plot(r,z_1) with this:

    plot(r,z_1,'.'); hold on

If you don't turn the "hold" to "on" then the figure is overwritten with each iteration.

You can also achieve this by adding these commands before the loop:

figure; hold on