accepts L, so the language is regular.
14. This is not easy to see. The trick is to use a dfa for L and modify it so that it
remembers if it has read an even or an odd number of symbols.
This can be done by doubling the number of states and adding O or E to the
labels. For example, if part of the dfa is
its equivalent becomes
Now replace every transition from an E state to an O state with λtransitions.