The reverse of a string x|, denoted rev x, is x written backwards. Formally, rev elementof =^def elementof, rev xa =^def a rev x. For example, rev abbaaab = baaabba. For A Subsetequalto sigma*, define rev A =^def {rev x | x elementof A}. For example, rev {a, ab, aab, aaab} = {a, ba, baa, baaa}. Show that for any A Subsetequalto sigma*, if A is regular, then so is rev A