How can I plot all iterations of my for loop?

Hey I'm kind of new to MALAB, so bear with me please!

I'm trying to plot the real and imaginary parts of the eigenvalue results in my for loop, as a function of I from [0,4].

Here's my code:

figure
hold on
for I = 0:0.1:4
    p = [-1/3 0 -1 (I-2)]
    r = roots(p)
    x = r(3)
    A = [(1 - x^2) -40 ; 1/800 -1/40]
    e = eig(A)
    plot(I,real(e(1)),'r-',I,imag(e(1)),'b-')
end

My plot keeps coming up empty, and no error shows up. what can i do?

Answer 1

[gonzalo Mier]

Right now, each plot is plotting only one point. To achieve the behavior you want, create the vectors and plot them outside the for loop

figure
hold on
e=[];
for I = 0:0.1:4
    p = [-1/3 0 -1 (I-2)]
    r = roots(p)
    x = r(3)
    A = [(1 - x^2) -40 ; 1/800 -1/40]
    e = [e,eig(A)]
end
 plot(0:0.1:4,real(e(1,:)),'r-',0:0.1:4,imag(e(2,:)),'b-')

[Lina Alami]

Thank you so much!!