diketahui f: R ⇒R dengan f(x) = 2x²+1 dan g(x) = x+2. tentukan : a. ( f o g ) (x) b. (g o f ) (3)

a)
fog(x)
= f(g(x))
f(x + 2)
= 2 (x+2)^2 + 1
= 2(x^2 + 4x + 4) + 1
= 2x^2 + 8x + 8 + 1
= 2x^2 + 8x + 9

B)

gof(3)
= g(f(3))

f(3) = 2(3)^2 + 1
= 2(9) + 1
= 19

g(19)
= 19 + 2
= 21