Write the Regular expression for the language of all consecutive even length a’s ?

Accepted Strings: 

These all strings are the part of the language so should be accepted by regular expression;

Example strings = {aa, aab, aabaa, aabbaa, aababaa,………}and all other strings that contains consecutive even a’s.

Rejected Strings:

These all strings are not part of the language so should be rejected by regular expression;

Example strings = {a, b, ab, ba, aba, bba, abba,……………..} and all other strings that does not contains consecutive even a’s in strings.

R.E = aa (a+b)^*ba

Part 1	Part 2	Part 3
aa	(a+b)*	ba