JEE Mains · Maths · STD 12 - 3 and 4 . metrices and determinant
The number of distinct real roots of \(\left|\begin{array}{lll}\sin x & \cos x & \cos x \\ \cos x & \sin x & \cos x \\ \cos x & \cos x & \sin x\end{array}\right|=0\) in the interval \(-\frac{\pi}{4} \leq x \leq \frac{\pi}{4}\) is
- A \(1\)
- B \(2\)
- C \(3\)
- D \(4\)
Answer & Solution
Correct Answer
(A) \(1\)
Step-by-step Solution
Detailed explanation
\(\left|\begin{array}{lll} \sin x & \cos x & \cos x \\ \cos x & \sin x & \cos x \\ \cos x & \cos x & \sin x \end{array}\right|=0\), \(\frac{\pi}{4} \leq x \leq \frac{\pi}{4}\) Apply: \(R_{1} \rightarrow R_{1}-R_{2}\) and \(R_{2} \rightarrow R_{2}-R_{3}\)…
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