diketahui fungsi f dan g dengan f (x) = x2+1 dan g(x) = 2x+4, tentukan (gof)-1 ( 2)

f(x) = x^2 + 1
g(x) = 2x + 4
(gof)^-1 (2) = ?

gof (x) = 2(x^2 + 1) + 4
gof (x) = 2x^2 + 6
y = 2x^2 + 6
y - 6 = 2x^2
(y - 6)/2 = x^2
[tex] \sqrt{(y - 6)/2}[/tex] = x

jadi
y = [tex] \sqrt{(x - 6)/2}[/tex]
(gof)^-1 (x) = [tex] \sqrt{(x - 6)/2}[/tex]
(gof)^-1 (2) = [tex] \sqrt{(2 - 6)/2}[/tex]
(gof)^-1 (2) = [tex] \sqrt{-4/2}[/tex]
(gof)^-1 (2) = [tex] \sqrt{-2}[/tex]