Question

Jika f(x) =(1+4Xkuadrat)(2-x) maka 2[f'(-1)] adalah...
tolong yaahh...aku lagi mau ikutin ujian ptn..makasih

Answer 1

F(x) = (1 + 4x²) (2 - x)
f(x) = 2 - x + 8x² - 4x³
f(x) = - 4x³ + 8x² - x + 2
f'(x) = 3.-4 x² + 16 x - 1
f'(x) = -12 x² + 16 x - 1
f'(-1) = -12.(-1)² + 16.(-1) - 1
= -12 . 1 - 16 - 1
= -12 - 16 - 1
= -29
maka 2.f'(-1) = 2.-29 = -58