1

(a)

Let

Note that:

THus the DSGF of is

(b)

Let for n=1,2,... thus:

It follows from (a) that the DSGF of is

2.

(c)

The first equality is true since all the other terms are zero.

(a) Let

Note that: by (c)

Applying (c) again: and

Multplying:

Therefore we must have: