Question

How can I draw i.e. x = 5 line in plot at Matlab?

I plot like that:

x = (-10:.1:10); 
f= 10;
plot(x, f, 'r');

of course it doesn’t work. For every variable of x, y is equal to 0 except for x=10. When x = 10 y equals to everything. How to plot this?

Answer 1

In MATLAB, plot(X, Y) simply draws points on the graph (and connects them with lines). Note that in this form of syntax, X and Y must have the same dimensions. Therefore, to plot the line x = 5 create a vector of your desired y-coordinates, and then create matching x-coordinates, which are all equal to 5:

Y = -10:0.1:10;
X = 5 * ones(size(Y));
plot(X, Y);