full work out with explanation of this problem please we're working with derivatives and i don't understand it

Question

given h(x)= cotx/x find h'(pi/2)

Answer 1

h = f/g so
h' = (f'g - fg')/g^2

h'(x) = [-x csc^2(x) + cot(x)]/x^2

h'(pi/2) = [-pi/2 * 1 + 0]/(pi^2 / 4)
= - 2/pi