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Question 200011
JEE Mathematics · Medium

Trigonometry: Double Angle MCQ

Solve this quality-checked JEE multiple-choice question, then review the correct answer and explanation.

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Double AngleMediumQuestion 200011

Question

cos 2θ can be written as:
  1. A
    1 − sin²θ
  2. B
    sin²θ − cos²θ
  3. C
    cos²θ − sin²θ
    Correct
  4. D
    2 sin θ cos θ

Correct answer

cos²θ − sin²θ

Explanation

cos 2θ = cos(θ+θ) = cos²θ − sin²θ. It can also be written as 2cos²θ − 1 or 1 − 2sin²θ.

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