MATLAB Plotting System of Equations in MATLAB

[FrogPad]

Maybe not the proper place to post... but it seems like physics forums is going through some type of "crazy" change right now. Anyways... I'm having trouble finding a website with directions on how to plot a system of equations in MATLAB. If anyone has a basic M-file they could show me, or a tutorial... that'd be really awesome! Thanks for the help :)

 

[enigma]

x=[-5:.1:5]; % x is a vector containing the numbers -5, -4.9, -4.8, ..., 4.9, 5. Semicolon means don't display to screen
y=4x.^3 - 2x.^2 - 12; % The '.'^ raises each element of the vector to the power listed. 
                                % If you just did ^ it would do matrix multiplication which doesn't work unless the matrix is square.

plot(x,y,'r*') % Plot variable X on the horizontal axis, y on the vertical, and display the points as red stars

Is that what you wanted, or did you need something more?

 

[FrogPad]

Actually, I already knew about the plot command. What I didn't know is that you can plot multiple equations with it.

t1=0:.1:10;
t2=10:.1:20;
y1=t1.*1;
y2=t2./t1;

plot(t1,y1,'r-',t2,y2,'r2-',...

But thanks for the reply

 

[enigma]

Ah, ok.

You can also skip the 'xxx' and have it automatically assign the colors.

Another way to do it is to hold the plot like so:

figure(1)

plot(x1,y1)

hold on

plot(x2,y2)
plot(x3,y3)

hold off

You can also simply type 'hold' to toggle it.