Dengan caranya yah ka, mohon bantuannya

y = (1 + cos x)/(sin x) = u/v
u = 1 + cos x => u' = -sin x
v = sin x => v' = cos x

y' = (u' v - v' u)/(v^2)
= (-sin x . sin x - cos x (1 + cos x))/(sin^2 x)
= (-sin^2 x - cos x - cos^2 x) / (sin^2 x)
= (-(sin^2 x + cos^2 x) - cos x) / (sin^2 x)
= (-1 - cos x) / (1 - cos^2 x)
= -1(1 + cos x)/(1 + cos x)(1 - cos x)
= -1/(1 - cos x)

= 1/(cos x - 1)