jika f(x)=ax^3-12x-5 melalui (-1,5) maka nilai maksimum f(x) untuk x E (1,2) adalah

Fungsi

f(x) = ax³ - 12x - 5
Melalui (-1,5)
f(-1) = 5
a(-1)³ - 12(-1) - 5 = 5
-a = 5 - 7
a = 2

maksimum --> f'(x) = 0
f(x) = 2x³ - 12x - 5
f'(x) = 0
6x² - 12 = 0
x² = 2
x = -√2 atau x = √2

f(-√2) = 2(-√2)³ - 12(-√2) - 5
f(-√2) = -4√2 + 12√2 - 5
f(-√2) = 8√2 - 5

f(√2) = 2(√2)³ - 12(√2) - 5
f(√2) = -8√2 - 5


Maksimum, f(x) = 8√2 - 5