### Home > CALC > Chapter 3 > Lesson 3.2.3 > Problem 3-74

3-74.

General form of a left-endpoint Riemann sum:

Hint for choosing the number of rectangles, *n*: While you want to choose a large value for *n*, be mindful that you will use that value to compute Δ*x*.

Since *b* − *a* = 8, it is recommended (though not necessary) that you choose an *n* that is divisible by 8.

You should have recognized that this function is a semi-circle with center at the origin and radius 4. The exact area can be found with geometry.

Use the eTool below to visualize this problem.

Click the link at right for the full version of the eTool: Calc 3-74 HW eTool