I have been trying to find an exampke fo an automorphism of $ℚ$.
I have tried with some simple equations, such as
$$a + n$$
$$n*a$$
$$a^n$$
(being $a$ an element in $ℚ$ and $n$ a constant)
None of the latter examples form an automorphism. There is clearly the identity, but that is kind of trivial.
So I was wondering, could someone provide an example of an automorphism of $ℚ$ besides the identity?
Any help/thoughts would be really appreciated.