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Let A and B denote the statements A: cos α+cos β+cos γ=0 B: sin α+sin β+sin γ=0 If cos (β-γ)+cos (γ-α)+cos (α-β)=- 3 2, then

JEE Main 2009 — Mathematics Algebra

2009mcqmedium

Let AAA and BBB denote the statements A: cos⁡α+cos⁡β+cos⁡γ=0\cos \alpha+\cos \beta+\cos \gamma=0cosα+cosβ+cosγ=0 B: sin⁡α+sin⁡β+sin⁡γ=0\sin \alpha+\sin \beta+\sin \gamma=0sinα+sinβ+sinγ=0 If cos⁡(β−γ)+cos⁡(γ−α)+cos⁡(α−β)=−32\cos (\beta-\gamma)+\cos (\gamma-\alpha)+\cos (\alpha-\beta)=-\frac{3}{2}cos(β−γ)+cos(γ−α)+cos(α−β)=−23​, then

Official previous-year question

Held on 30 Apr 2009 · Verified 6 Jul 2026.

Options

  1. A

    AAA is true and BBB is false

  2. B

    AAA is false and BBB is true

  3. C

    both AAA and BBB are true

  4. D

    both AAA and BBB are false

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