Angle Addition Formulas (Trigonometry)
[asy]
real a,b,c;
a=0.4924;
b=0.5467;
c=a+b;
pair A,B,C,D,E,F;
A=(0,0);
D=(cos(c),sin(c));
B=(cos(a)*cos(b),0);
C=(cos(a)*cos(b),sin(a)*cos(b));
draw(A--B--C--D--cycle);
draw(A--C);
E=foot(D,A,B);
draw(D--E);
F=foot(C,D,E);
draw(C--F);
draw(anglemark(B,A,C,4));
draw(anglemark(C,A,D,5.5));
label("
", A ,7*dir(a*30));
label("
", A ,9*dir(b*45+ a*30));
[/asy]
