### Home > CALC > Chapter Ch3 > Lesson 3.1.1 > Problem 3-9

3-9.

Write an expression using sigma notation that represents the sum of the areas of the rectangles shown for the function below. Note, the rectangles have equal widths. Homework Help ✎

Questions to consider:

How many rectangles are there, *n*?

Are they left-endpoint, right-endpoint or midpoint rectangles?

Left-endpoint:

Right-endpoint:

Midpoint:

What is the width/base of each rectangle, Δx?

What is the function?

What is the starting value, a?

On what interval is the area being approximated?