Let `f: N->N` be defined by: `f(n)={n+1,\ if\ n\ i s\ od d n-1,\ if\ n\ i s\ e v e n` Show that `f` is a bijection.

Explanation

Given:

`f(n)={
n+1`,if n is odd

`n−1`,if n is even

Check one -one:

Case I: If n is odd,

Take `x_1,x_2
in N` such that `f(x_1)=f(x_2)`

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