Page 49 - E-MODUL Fungsi komposisi dan fungsi invers

3. f o g (x) = f (g (x))

f (g (x)) = 4x – 2

2
f ( + 1) = 4x – 2
2
f (x) = 4 ( + 1) – 2
2
= 4 + 4 – 2 20
2
= 4 + 2
Jika f (n) = 18 , maka

f (n) = 18

2
4 + 2 = 18
2
4 = 18 – 2
2
4 = 16
16
2
=
4
2
= 4

= √4

n = 2

jadi, nilai n adalah 2.

4. a. f o g (x) = f (g(x))

= f (3x)

= 2 (3x) + 4

= 6x + 4

((f o g) o h) (x) = f o g (h(x))

2
= f o g (2 - 1)
2
= 6 (2 - 1) + 4
2
= 12 – 6 + 4
2
= 12 – 2 10

Modul Elektronik Menggunakan Pendekatan Kontekstual | 41