(2*(cos((1))*cos(b) – cos((1) + b)))/(cos((1) – b) – 2*sin((1))*sin(b))
(2*(cos(1)*cos(b) – cos(1 + b)))/(cos(1 – b) – 2*sin(1)*sin(b))
(-2*cos(1 + b) + 2*cos(1)*cos(b))/(-2*sin(1)*sin(b) + cos(-1 + b))
2.0*(-cos(a + b) + cos(a)*cos(b))/(-2.0*sin(a)*sin(b) + cos(a – b))
2*sin(a)*sin(b)
—————
cos(a + b)
-1 + cos(a – b)*sec(a + b)
-(2*cos(a + b) – 2*cos(a)*cos(b))
———————————-
-2*sin(a)*sin(b) + cos(a – b)
2*sin(a)*sin(b)
—————
cos(a + b)
-2*(-cos(a)*cos(b) + cos(a + b))
——————————–
-2*sin(a)*sin(b) + cos(a – b)
2*sin(a)*sin(b)
—————————–
cos(a)*cos(b) – sin(a)*sin(b)