What is the value of the sum of the infinite series 1 - 1 + 1 - 1 + ...?
Correct: D
This is an alternating series, and we can use the formula for the sum of an alternating series to find its sum. However, a simpler way to evaluate this series is to group its terms: (1 - 1) + (1 - 1) + (1 - 1) + ... . Each group of terms in parentheses has a sum of zero, so the sum of the entire series is zero.