F(x)=x2-4 dan g(x)=4-x2 Tentukan rumus fungsi dari (fog)(x)dan (gof)(x)

f(x) = x² - 4
g(x) = 4 - x²

Jawab:
(fog)(x) = f(g(x))
(fog)(x) = (4 - x²)² - 4
[tex](fog)(x) = 16 - 8 { x}^{2} + {x}^{4} - 4 [/tex]
atau
[tex](fog)(x) = {x}^{4} - {8}x^{2} + 12[/tex]

(gof)(x) = g(f(x))
(gof)(x) = 4 - (x² - 4)²
[tex](gof)(x) = 4 - ( {x}^{4} - 8 {x}^{2} + 16)[/tex]
[tex](gof)(x) = 4 - {x}^{4} + 8 {x}^{2} - 16[/tex]
atau
[tex](gof)(x) = - {x}^{4} + 8 {x}^{2} - 12)[/tex]