### Home > CCA2 > Chapter 10 > Lesson 10.2.1 > Problem 10-89

10-89.

Consider the series

How many terms are there?

Write an expression for the sequence, and find

when.

What is the sum?

Use the summation formula

10-89.

Consider the series

How many terms are there?

Write an expression for the sequence, and find

when.

What is the sum?

Use the summation formula