8. a) A 2xn checker board needs to be tiled by 2x1 tiles. Write a recurrence relation that describes the number of ways in which a 2xn checker board can be tiled by 2x1 tiles. Explain the recurrence relation b) Using the recurrence relation in part a), find the number of ways in which a 2x6 checker board can be tiled by 2x1 tiles. Show all work