engineering mathematics MCQ #5578

If cos(x) = -1 / 2, what is cos(2x)?

engineering mathematics MCQ #5578

  1. Question 1

    Q1. If cos(x) = -1 / 2, what is cos(2x)?

    • A) -1 / 2
    • B) 1 / 2
    • C) -1
    • D) 1

    Answer: -1 / 2

    Explanation: Using cos(2x) = 2cos²(x) - 1, we find cos(2x) = -1 / 2.