Just get the vector returned by each of the local functions when you call them. Then you can plot them.
Pmax_1 = max_press1(W1, E1, R1);
plot(Pmax_1)
... and so on. How you choose to arrange the plots is up to you. Depending on the relationships between these values, you might put them in separate figures, or you might group them using subplot() or tiledlayout().
Just a heads up, the two functions for case 4 don't print the correct "results for case 4" message, although I don't know if you intend to keep the text output once the plots are available.
