2004 AMC 12A Problems/Problem 21
Problem
If $\sum_{n = 0}^{\infty}{\cos^{2n}\theta = 5$ (Error compiling LaTeX. Unknown error_msg), what is the value of ?
Solution
This is an infinite geometric series, which sums to . Using the formula .
See also
2004 AMC 12A (Problems • Answer Key • Resources) | |
Preceded by Problem 20 |
Followed by Problem 22 |
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All AMC 12 Problems and Solutions |