Question

Если f(x)=(1-2x)(2x+1), то найдите f''(1)

Answer 1

f(x)=1-4x^
f'(x)=-8x
f''(x)=-8
f''(1)=-8

Answer 2

(1-2х)' (2х+1) + (2х+1)' (1-2х) = -2(2х+1)+2(1-2х)=-4х-2+2-4х= - 8х

-8*1= -8