9. LetS, represent the number of dots in an a by n square array. Pretend you have forgotten that S. = n' . Give a recursion equation that tells how S,, is related to S, by reasoning how many extra dots are needed to form the (n + 1)st square array from the previous ath square array . Illustrate your answer with a diagram of dots. Use a generic picture to show how to get S. if you have S