e) (4 points) Let s, = Z bi.. Use the definition of s and your work in part (b) to write out an unsimplified expression k=1 9 9 for s5. Then show how to simplify this sum to obtain s =2+ - = 3 f) (6 points) Look for the pattern in your work in part (e) and then use the pattern to write an explicit formula for s,,. Make sure you show how you obtain this explicit formula from the definition of s,,. Then determine a function f(x) of a continuous variable = such that f(n) = s, when n is a natural number