Nilai f'(-1) = ….
Penyelesaian:
f(x) = x – 4 berupa u(x).
3x + 2 v(x)
Misalkan:
u(x) = x – 4 ⇔ u'(x) = 1
v(x) = 3x + 2 ⇔ v'(x) = 3
Dengan demikian:
f'(x) = u'(x)v(x) – u(x)v'(x)
(v(x))²
= (1)(3x + 2) – (x – 4)(3)
(3x + 2)²
= (3x + 2) – (3x – 12)
(3x + 2)²
= 14
(3x + 2)²
Untuk x = -1 diperoleh:
f'(-1) = 14
(3(-1) + 2)²
= 14
(-3 + 2)²
= 14
(-1)²
= 14
Jadi, nilai f'(-1) = 14.