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CUET · MATHS · PYQ PAPER 2023

The value of the determinant \(\left|\begin{array}{ccc}\cos ^2 \theta & \cos \theta \sin \theta & 0 \\ -\sin \theta & \cos \theta & 0 \\ 0 & 0 & 1\end{array}\right|\) is equal to

  1. A 1
  2. B \(\cos \theta\)
  3. C \(\cos 2 \theta\)
  4. D \(\cos \theta-\sin \theta\)
Verified Solution

Answer & Solution

Correct Answer

(B) \(\cos \theta\)

Step-by-step Solution

Detailed explanation

\( \left|\begin{array}{ccc}\cos ^2 \theta & \cos \theta \sin \theta & 0 \\ -\sin \\ \theta & \cos \theta & 0 \\ 0 & 0 & 1\end{array}\right| = 1 \cdot \left|\begin{array}{cc}\cos ^2 \theta & \cos \theta \sin \theta \\ -\sin \theta & \cos \theta\end{array}\right| \)…