### Home > CALC > Chapter 9 > Lesson 9.1.1 > Problem 9-15

9-15.

Ying has a different method for summing an infinite series. Here are her steps:

Let

the sum.Separate the first term from the rest of the series.

Factor the rest of the terms so that the remaining factor is

.Substitute

for the other factor.Solve for

.

Apply Ying's method to find * *in the following problem. The first three steps are done for you. Copy them first, then complete the solution.