MATLAB: Solving differential equation with imaginary unit

differential equationimaginary unit

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I have these equations. k and sigma are variables which i can set as i want, "j" is imaginary unit. I wrote this code: 
d = 2;
k = 2;
syms Af(z) Ab(z)
ode1 = diff(Af) == 1j*d*Af + 1j*k*Ab;
ode2 = diff(Ab) == -1j*d*Ab - 1j*k*Af;
odes = [ode1; ode2]
cond1 = Af(0) == 1;
cond2 = Ab(0) == 0;
conds = [cond1; cond2];
[AfSol(z), AbSol(z)] = dsolve(odes,conds)
fplot(AfSol)
hold on
fplot(AbSol)
grid on
legend('AfSol','AbSol','Location','best')
but graph is not painted. I don't know why.

Best Answer

The plot functions onnly plot real values. If you ask for the imaginary parts, you will see the results: 
fplot(imag(AfSol))
hold on
fplot(imag(AbSol))
grid on
legend('AfSol','AbSol','Location','best')
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