First time here? Check out the FAQ!
answered 7 years ago
You must use trig_reduce():
trig_reduce()
sage: exp1.trig_reduce() sin(x1 + x2)
updated 7 years ago
The reverse operation is trig_expand():
trig_expand()
sage: exp2 = sin(x1 + x2) sage: exp2.trig_expand() cos(x2)*sin(x1) + cos(x1)*sin(x2)