I’m not the best in Maths, but for what I am doing now I need to calculate the angle of the vector which is shown as arrow in the picture below:

I have a point A and a point B in a 2D plane. I need to calculate the following:
- The angle in which the arrow must be rotated in order to point to B
atan2(yB-yA, xB-xA), assuming your library hasatan2. Otherwise you need to useatan, which will return the correct answer if B is to the right of A, and will be 180 degrees off otherwise. Also note that the return value is in radians, you can convert radians to degrees by multiplying by180/piif necessary.Wikipedia has a detailed explanation of the geometry.