### Home > CALC > Chapter 2 > Lesson 2.2.3 > Problem 2-85

2-85.

Jamal wrote the following Riemann sum to estimate the area under

*f*(*x*) = 3*x*^{2}− 2. Homework Help ✎

Draw a sketch of the region. How many rectangles did he use?

For what domain of

*f*(*x*) did Jamal estimate the area?Use the summation feature of your calculator to find the approximate area using Jamal's Riemann sum.

General form of left-endpoint Riemann Sum:

*n* − 1 = 9 *n* = 10 There are 10 rectangles.

The function is *f*(*x*) = 3*x*² − 2

*a* = −3 This is where the region starts.

Refer to the graph in part (a).

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