The tangent of the sum of two angles

Question:
tan(a + b) = ?
Proof:
proof the formula of the tangent angles sum
Formula used:
tan(a) = sin(a)/cos(a)
sin(a + b) = sin(a) cos(b) + cos(a) sin(b)
cos(a + b) = cos(a) cos(b) - sin(a) sin(b)