plot symbolic function real part

Hello there,

I would like to plot the real part of this symbolic function I have just solved.

Parameters 'a' and 'e' are varying between 5 and 9, and 0.05 and 0.15 respectively.

Unfortunately, it does not work.

Here you go with my code ( solution is a ratio of sum of Bessel functions of order zero).

clc
clear

set(groot,'DefaultAxesFontSize',14) 
set(groot,'DefaultLineLineWidth',1.5)
syms a e

A = [besselj(0,-1i*a*e), bessely(0,-1i*a*e); ...
    besselj(0,-1i*a), bessely(0,-1i*a)];
b = [-1; -1];
X = linsolve(A, b);
disp(X)

a = linspace(5,9);
e = linspace(0.05, 0.15);
plot(a, e, X)

Answer 1

[Star Strider]

You are plotting a function of two variables, so you need to use a plot that accommodates them, and that your function is symbolic.

Try this:

syms a e
A = [besselj(0,-1i*a*e), bessely(0,-1i*a*e); ...
    besselj(0,-1i*a), bessely(0,-1i*a)];
b = [-1; -1];
X = linsolve(A, b);
disp(X)
a = linspace(5,9);
e = linspace(0.05, 0.15);
fsurf(real(X), [5 9, 0.05 0.15])
xlabel('a')
ylabel('e')

Experiment to get the result you want.

[john_arle]

Thank you. Any other options that fsurf that I can try?

regards,

Andrea.

[Star Strider]

As always, my plesure.

There are several 3D plots that will probably work with your system. See the documentation on fcontour (link), fmesh (link), and fplot3 (link).