Misalkan f dan g adalah fungsi sehingga f ^-1 (x) = g(x). Tentukan f(f(1)) jika g(20) = 1, g(1) = 7, dan g(7) = 20.

jawab

f⁻¹ (x ) = g(x)
f { g(x)} = x

g(20)= 1 --> f { g(20)} = 20
f(1) = 20

g(1)= 7 --> f{ g(1)} = 1
f(7) = 1

g(7) = 20 --> f {g(7)} = 7
f(20) = 7


nilai f { f(1)} = f {20} = 7