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CUET · MATHS · PYQ PAPER 2025

If \(\left|\begin{array}{ccc}1 & \cos \theta & 0 \\ \sin \theta & 1 & \cos \theta \\ \cos \theta & 1 & -\sin \theta\end{array}\right|=A \sin \theta+B \cos \theta+C \sin \theta \cos \theta\) then :

  1. A \(A+B=0\)
  2. B \(B+C=2\)
  3. C \(C+A=1\)
  4. D \(B-A=1\)
Verified Solution

Answer & Solution

Correct Answer

(D) \(B-A=1\)

Step-by-step Solution

Detailed explanation

\(D = 1(1(-\sin\theta) - \cos\theta(1)) - \cos\theta(\sin\theta(-\sin\theta) - \cos\theta(\cos\theta))\) \(D = -\sin\theta - \cos\theta - \cos\theta(-\sin^2\theta - \cos^2\theta)\) \(D = -\sin\theta - \cos\theta - \cos\theta(-1)\) \(D = -\sin\theta\) \(A = -1, B = 0, C = 0\)…