Self Doubt

Question

S -> AS | b

A -> SA | a

Find First and Follow set for folowing grammar

Answer 1

First (s)=a,b

First (A)=a,b

Follow (s)=$,a,b

Follow (A)=a,b

Answer 2

	First	Follow
S->AS | b	a, b	a, b, $
A->SA | a	a, b	a,b,$

Few observations: 

Follow of Starting symbol always contains $ since, input is followed by $ and 

if Start symbol is present in RHS of any production then follow of that production also contains $. 

Comments

How Follow of A contain $