All solutions here are SUGGESTED. Mr. Teng will hold no liability for any errors. Comments are entirely personal opinions.
Width of each rectangle
Total area of rectangles
When , we have the exact area instead.
(i) needs some explanations to be done and there are many ways to present it, just make sure you use a graph. They are looking for students to be able to write out the definition of integration here. This question should be one of those “high A” questions to set students apart. You don’t have to use summation signs here too. (ii), we can check answer with GC.