turunan kedua dari f(x) = (2x-1)³ di x = 2 adalah.....

f'(x)=3(2x-1)² . 2
f''(x)=3.2(2x-1).2.2
f''(2)=6.4.3=72

Ingat rumus:
Jika f(x) = [u(x)]ⁿ, maka f'(x) = n[u(x)]ⁿ⁻¹ .u'(x)

Penyelesaian:
f(x) = (2x-1)³
f'(x) = 3.(2x-1)³⁻¹ .2
f'(x) = 6.(2x-1)² 
f''(x) = 6.2(2x-1)²⁻¹ .2
f''(x) = 24.(2x-1)

Maka, x = 2 adalah:
f''(x) = 24.(2x-1)
f''(2) = 24.(2.2-1)
f''(2) = 24.(4-1)
f''(2) = 24.3
f''(2) = 72