Build regular expressions for the following languages a w ab

Build regular expressions for the following languages.

a) {w {a,b}*: w contains at least two b\'s}

b){w {a,b,}*:every even position of w is b}

c){w {a,b,}*:w contains no consecutive b\'s}

Solution

Here are the regular expressions:-

a) (a+b)^*b(a+b)^*b(a+b)^*

b) (ab)(ab)*

c) (a+ba)^*b(a+ab)^*