Connecting two data points in a plot with a line, and determining this line's slope

Hello,

I have an excel sheet of a lot of data points (X and Y coordinates), and I have inserted these data into matlab and plotted the figure.

On the figure, I want to connect one data point to another one, and then determine the slope of this line.

It is easy to just write down the coordinates of the two data points and calculate the slope, but I cannot do it manually like this because I have to do it many times for different data points.

Is it possible to do it on the figure to immediately get the line and its slope?

[dpb]

Of course it is, but you've got to have some way to determine which two specific points; the Clairvoyant Toolbox™ is yet to be released...

Answer 1

[dpb]

For just between two points, may as well just use

m=(y2-y1)./(x2-x1);     % slope between two points

Or, if specify by choosing two indices, then if the two indices are i1, i2 use

m=(y(i2)-y(i1))./(x(i2)-x(i1));     % slope between two points, i1 and i2 indices