
Doug C. answered 04/17/21
Math Tutor with Reputation to make difficult concepts understandable
The numerator in the 3/n (which represents the width of each of n rectangles) is calculated as -> (b-a)/n.
Since k starts at 1,using right hand endpoints, which means 3k/n is what is added to a to get each of the right-hand endpoints
Each xi (right hand endpoint) is plugged into a function x2.
So the definite integral is:∫74 x2 dx.
Check out this page for confirmation:
desmos.com/calculator/kxh1q3oda1