I’m currently making a 2D flight game and I’m having trouble making the AI.

I have the coodinates of A and B and I want to get the angle Alpha.

I know a formula that I can use if I had the coordinates of C but I can’t find a way to get it right.

I don’t know the coordinates of any of the 2 vectors I just know the coordinates of point A and B.

Can someone help me ?