
Mark H. answered 01/03/20
Tutoring in Math and Science at all levels
Do you mean y = (1 + sin(x)) / (1 - cos(x))
Use the quotient rule: d/dx (u/v) = (v*u' - u*v') / v2
So, y' = { (1 - cos(x)) * cos(x) - (1 + sin(x)) * sin(x) } / (1 - cos(x))2
Simplify the top: cos(x) - cos2(x) - sin(x) - sin2(x) = cos(x) - sin(x) - 1
(cos(x) - sin(x) - 1) / (1 - cos(x))2