### Home > CALC > Chapter 2 > Lesson 2.2.2 > Problem 2-69

2-69.

Using sigma notation, write a Riemann sum to estimate the area under the function for

Since area of a rectangle

Next, find the height of each rectangle. The height is determined by , where

*starting value on the*

*-axis.*

Finally, use sigma notation to represent the sum of all eight rectangles. Since these are left-endpoint rectangles, the index will start at , where

*number of rectangles.*

Use your calculator to evaluate this sum.