Page 28 - E-MODUL FUNGSI KOMPOSISI DAN FUNGSI INVERS

-1
f (k) = 4 − 2
3 −2
2 = 4 − 2
3 −2
2 (3k – 2) = 4k - 2
6k – 4 = 4k – 2

6k – 4k = -2 + 4
2k = 2

2
k =
2
k = 1

Contoh 3:
3
Ditentukan f(x) = 2x – 3, g(x) = x + 2 dan h(x) = , x ≠ 0. Carilah nilai x sehingga

–1
(ℎ ) ( ) = 1!
Penyelesaian:
( )( ) = (2x – 3) + 2 = 2x - 1

(ℎ ( ))( ) = 3
2 −1
Misalkan (ℎ ( ))( ) = y, maka:

y = 3
2 −1
2xy - y = 3

2xy = 3 + y

x = 3+
2
-1
(ℎ ( )) ( ) = 3+
2
1 = 3+
2
2x = 3 + x
2x - x = 3

x = 3

Contoh 4:
Diketahui f(x) = 3x - 4, tentukan:

-1 -1
a. ( ) ( )
-1
-1
b. ( )( ) dan ( )( )

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