hey I was having some trouble here and I was wondering if anybody could assist me.

Show that (1 2 3 4 5) is conjugate to (1 3 5 2 4) in $\displaystyle S_5 $ but not in $\displaystyle A_5 $.

Clearly (4 5 3 2) will work and this is odd, so not in A5. but why can't we find an even permutation that will work for the conjugation?