Question

Diketahui f(x) = px^3 - x^2 + 5. jika f" (1)= 10 , nilai f' (-1) =......?

Answer 1

F(x) = px³ - x² + 5
f '(x) = 3px² - 2x
f ''(x) = 6px - 2
Dengan f ''(1) = 10
Maka,
6p(1) - 2 = 10
6p - 2 = 10
6p = 12
p = 2

Sehingga,
f '(x) = 3px² - 2x
f '(x) = 3(2)x² - 2x
f '(x) = 6x² - 2x
Dan,
f '(-1) = 6(-1)² - 2(-1)
f '(-1) = 6(1) + 2
f '(-1) = 6 + 2
f '(-1) = 8