### Home > APCALC > Chapter 9 > Lesson 9.4.2 > Problem 9-127

9-127.

Timmy is tired. He does not

How far is his result from the actual sum of the infinite series? (This is called his “error.”)

For an infinite geometric series:

What would his error have been if he added the first four terms?

Generalize his error. That is, if he adds up

terms of this geometric series, what will his error be?For a finite geometric series:

Substitute

andinto the formulas in the hints then evaluate.