How can I plot y=mx+b in Matlab?

Question

I was wondering if it is possible to plot a line of the form y = mx+b in Matlab? I used polyfit to get a 1x2 array that contains the slope and intercept.

Here is what I have so far:

lineFit = polyfit(tauBin, a5array, 1);
plot((lineFit(1)*x + lineFit(2)))

How can I plot this?

Solution 1

There are two way that immediately come to mind. The first is with FPLOT:

>> m = 2; b = 1;
>> fplot(@(x)m*x+b, [0 10]);

The second is to calculate the y values directly in the call to the PLOT command:

>> m = 2; b = 1; x = 1:10;
>> plot(x, m*x+b);

Solution 2

There is REFLINE function in Statistical Toolbox. Probably the easiest for your task:

refline(m,b)

or if you want to change line properties:

hr = refline(m,b);
set(hr,'Color','r')

It uses limits from the current axes. So if you change the limits later, it probably would be easier to delete it (delete(hr)) and draw again.