angle between three points please help

for f=1:h
    t=(f-1)*k/20;
    m=f+1;
    P0=[171.5 239.5]; %střed [x,y]
    P1=[htabulka(1,1),htabulka(1,2)]; %XY1 [x,y]
    P2=[htabulka(f,1),htabulka(f,2)]; %XY2 [x,y]
    ang = atan2(norm(det([P2-P0;P1-P0])),dot(P2-P0,P1-P0));
    angst=ang*180/pi
    cosf=cos(angst);
    ....

I have this part of code

I have a object rotating --> but this angle only gives me max 30 degrees but that is not posible becaouse the object is making circle

one point the center is always the same, than the beginning point is also the same, and one point is moving due to video --> so the degrees suposed to get from 0 to 360 but it gives me this

[Torsten]

ang = atan2(norm(det([P2-P0;P1-P0])),dot(P2-P0,P1-P0));

Could you show us where you got this strange formula from ?

[Jeffrey Clark]

@Eliska Paulikova, @Torsten I assume this was answered in your question

how to find concave angle between three points

[Torsten]

The OP posted three different questions on the same subject.

This one was no longer used.