Turunan pertama dari k(x) = cos x cotan x adalah k'(x) = . . . .(dengan cara kerjanya)

k(x) = cosx . cotx

u = cosx
u' = -sinx

v = cotx
v' = -csc²x

k'(x) = u'v + v'u
k'(x) = (-sinx)(cotx) + (-csc²x)(cosx)
k'(x) = (-sinx)(cosx/sinx) + (-csc²x)(cosx)
k'(x) = (-cosx) + (-1/sin²x)(cosx)
k'(x) = (-cosx) - cosx/sin²x
k'(x) = -cosx - cosx/sin²x
k'(x) = cosx + cosx/sin²x
k'(x) = cosx (1 + 1/sin²x)
k'(x) = cosx (1 + csc²x)