4. Solve the following recurrence relations: (a) an = 2an - 1 where a0 = 1 [9 marks] (b) an = 3an - 1 where a0 = 2 [9 marks] (c) Given the sequence 1, 2, 5, 10, 17, 26, ...... where a1 = 1, a2 = a1 + p and a3 = a2 + q, ..... where p, q, r, ....are consecutive odd numbers. (i) Write the equation for a4. [2 marks] (ii) Find the values of p, q and r. [3 marks] (iii) Find the answer for a7 and a8. [2 marks] [Total: 25 marks]