Question

(UFAM) Se f(x) = (2x-1)⁴, então f'(1) será:

Answer 1

chamemos u=2x-1. Assim, f'=df/du . du/dx=4u . 2=8(2x-1)=16x-8

Answer 2

$f(x)=(2x-1)^4\\\\f'(x)=4\cdot(2x-1)^3\cdot(2)\\\\f'(x)=8(2x-1)\\\\f'(1)=8(2\cdot1-1)\\\\f'(1)=8(2-1)\\\\\boxed{f'(1)=8}$