GX = 2 x + 1 F komposisi g x = x ^ 2 + x FX =

g(x) = 2x + 1 dan f o g (x) = x^2 + x
f { g(x) } = x^2 + x
f (2x + 1) = x^2 + x
f (2x + 1) = 1/4(2x + 1)^2 - x - 1/4 + x
f (2x + 1) = 1/4(2x + 1)^2 - 1/4
f (x) = 1/4x^2 - 1/4
f (x) = 1/4(x^2 - 1)

Dik: g(x)=2x+1 , fog(x)=x^2+x
Dit f(x)=...?
Jawab

fog(x)=x^2+x
f(g(x))=x^2+x
f(2x+1)=x^2+×
f(x)=(x-1/2)^2+(x-1/2)
f(x)=(X^2-2x+1 /4) +(2x-2/4)
f(x)= (x^2-1/4)