Bonjour,
f(x) = 4 / ( 2x + 1 )⁴
f(x) = u / v
u = 4
u' = 0
v = ( 2x + 1 )⁴
v' = 4 × ( 2x + 1 )³ × 2 = 8 × ( 2x + 1 )³
f'(x) = ( u'v - uv' ) / v²
f'(x) = [ 0 × ( 2x + 1 )⁴ - 4 × (8 × ( 2x + 1 )³) ] / ( 2x + 1)⁸
f'(x) = [ -16 × (2x + 1)³ ] / (2x + 1)⁸
En espérant t'avoir aidé, bonne continuation ;)
