### Home > PC3 > Chapter 4 > Lesson 4.2.2 > Problem 4-78

4-78.

Complete the following problems about sigma notation.

Expand the summation:

Write the following using sigma notation:

The argument (expression) is

. Write an expression for the '

's.The sum in part (b) could be a left endpoint approximation of an area under a curve. Which curve? What is the interval?