All instructor questions

3)  1 mark find A(x).  1 mark find coeff of x^n

4)  1/2 mark base case.  1.5 marks ind step

6)  One mark for determining you need the nth coeff of R(x)/(1-x).  One mark for
par frac and final proof.

9)  1 mark sufficiency.  1 mark necessity.

11)  1 mark odd case.  1 mark even case.

