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CBSE Class 12 Mathematics 2026 Main Paper 65/2/3 · Q191 Marksdot_and_cross_products

CBSE Class 12 Mathematics 2026 Main Paper 65/2/3 · Question 19 (Vector Algebra)

Assertion: |a×b|²+(a·b)²=|a|²|b|². Reason: |a×b|=(a·b) tan θ for θ≠π/2, where θ is the angle between the vectors.

✅ Step-by-Step Solution

Final Answer: Both are true but the reason does not explain the assertion.
  1. The assertion follows by adding the squared sine and cosine expressions, including the perpendicular case. The reason is true for its stated angles, but on its own does not establish the identity for every angle.

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