F(x) = 1/x ,f(f(f(f(f(f(x))))))=??

f(x) = 1/x ,f(f(f(f(f(f(x))))))=??

1 Answer
Jun 26, 2018

f is its own inverse, so an even number of them composed, six here, gets us back where we started:

f(f(f(f(f(f(x))))))=x

Explanation:

One application of f gives the reciprocal:

f(x)=1x

Two gives us the reciprocal of the reciprocal, which is x

f(f(x))=f(1x)=11x=x

Three applications give us 1x:

f(f(f(x)))=f(x)=1x

We see four applications gives us x, five gives us 1x, etc. An even number gives us x and an odd number 1x.