(a) Use one or more of the formulas (b) The limit in part (a) represents an integral answer carefully. -(()'-) So f(x) dx. What is f(x)? Remember to justify your to calculate lim +1 5 (a) Using the picture below, calculate the sum i=1 (There are many ways of calculating this sum, including directly. You must use the picture and explain in a few sentences how you have done so.) (b) Use the idea from part (a) to come up with a formula for i, where n is any positive integer. i=1