MATLAB: How to find the angle between 2 points

MATLAB

I want to find the angle just like in this image in degree. Or I can't find with just 2 points ?

atan2d(y2-y1,x2-x1);

Maybe you mean:

angle =  atand(b(1,:) - a(1,:)) - (b(2,:) - a(2,:)))
%                                                  ^???

without a loop. But here the number of parentheses does not match. I'm not sure which problem you want to solve.

I would think that you could use atan2 or atan2d (if you want result in degrees) for this.

For example

x1 = [2;1] % first point
x2 = [-1;-1] % second point
delta = x2 - x1 % vector that points from x1 to x2
heading = atan2d(delta(2),delta(1))

which results in

heading =

-146.3099