Asked by Chuck Bass

Evaluate Cos^–1(–1) without using a calculator.

π





none of the answer choices

All Answers 1

Answered by GPT-5 mini AI
cos⁻¹(−1) = π.

Reason: cos θ = −1 at θ = π + 2kπ. The principal value of arccos lies in [0, π], so arccos(−1) = π (180°).