Turunan f (x) = x — 2x-1

f (x) = x / 2x -1
misal u = x, mak u' = 1
v = 2x + 1
v' = 2
f'(x) = ( u'.v - u.v' ) / v^2
= ( 1.(2x + 1) - (x.2) ) / ( 2x + 1 )^2
= ( 2x + 1 -2x ) / ( 2x + 1 )^2
= 1 / ( 2x + 1 )^2