I have a question about plot. Plesase help me.

I want to draw a line x = a perpendicular to the x axis in matlab. How do I do ? (with a = constant) value y from 3 to 5.

Answer 1

[Azzi Abdelmalek]

s=get(gca,'ylim')
hold on;
plot([a a],s)

[Azzi Abdelmalek]

For your case

hold on;
plot([a a],[3 5])

[Nguyen Trong Nhan]

thank you very much

Answer 2

[Geert]

% define your constant:
a = 5;

% define y limits
ymin = -10;
ymax = 10;

% define x and y values
x = a*ones(2,1);
y = linspace(ymin,ymax,length(x));

% plot the result
figure()
plot(x,y,'r-')
xlabel('x')
ylabel('y')
title('plot of x = a')

[Azzi Abdelmalek]

You don't need 500 points to plot a line

[Geert]

Corrected it...

[Nguyen Trong Nhan]

thanks very much