Question

find all strings of lenght 4 less, for the following regular expression (a*b + b*a)

Comments

Length 4 less means?

Please write the question properly.

Answer 1

if it is less than or equal to then the strings which can be generated are
0 length – 0 strings
1 length – a,b

2 length  – ab,ba

3 length – aab,bba
4 length – aaab,bbba