Unable to plot a graph

This is the given question I was asked to plot in one of my labs.

And below is my code for MATLAB.

However, I am not getting the graph for this first, second and the third part of the question. Can someone guide me where I went wrong in my code?

Answer 1

[Sulaymon Eshkabilov]

Here is the corrected complete code:

clearvars
syms lambda
Z_L = 25;
Z_C = 50;
z_L = Z_L/Z_C;

y=@(lambda)(Z_C*((z_L+1i*tan(2*pi./lambda))./(1+1i*z_L*tan(2*pi./lambda))));
Lam = linspace(0,2*pi, 500);
F = y(Lam); 
F = abs(F);

F(isnan(F))=0;
plot(Lam, F, 'rd--', 'markerfacecolor', 'c')
grid on
xlabel('$\lambda$', 'Interpreter','latex')
ylabel('$Z_{in}(\lambda)$', 'Interpreter','latex')
title('Load Impedance at 25 \Omega')
ylim([0, 105])
xlim([0, 2*pi])

[Adnan Habeb]

Hello. Thank you for responding to my question. I want to understand something.

What does these lines do?

I want to know what is the purpose for using these lines.

F = y(Lam);

F = abs(F);

F(isnan(F))=0;

Thank you