Jika g(x)=x^2-1 dan fungsi memenuhi (f bundaran g)(x)=x^4 maka f(4)=

g(x) = x² - 1
a = x² - 1 ---> x² = a + 1

(fog) = x⁴ = (x²)²
f(a) = (a + 1)²
f(x) = (x + 1)²