NDA 2025 · PYQ · Trigonometry · easy
What is 2sin2α + cos2α equal to?
Answer
The correct answer is B: 11/5. With sinα = 3/5, cosα = 4/5: sin2α = 2·(3/5)(4/5) = 24/25, cos2α = cos²α - sin²α = 16/25 - 9/25 = 7/25. So 2sin2α + cos2α = 48/25 + 7/25 = 55/25 = 11/5.
- A.11/10
- B.11/5✓ Correct
- C.12/5
- D.13/5
With sinα = 3/5, cosα = 4/5: sin2α = 2·(3/5)(4/5) = 24/25, cos2α = cos²α - sin²α = 16/25 - 9/25 = 7/25. So 2sin2α + cos2α = 48/25 + 7/25 = 55/25 = 11/5.
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