Determine whether or not the following languages are regular. If the language

is regular then give an NFA or regular expression for the language. Otherwise, use the

pumping lemma for regular languages or closure properties to prove the language is not

regular.

$($a$)$ L $=\{$a$^($n$^2)|$ n $>=1\}.$

$($b$)$ L $=\{$a$^$n $|$n is not a multiple of $5\}.$