WBJEE · Maths · Determinants
Let \(A=\left[\begin{array}{ccc}5 & 5 \alpha & \alpha \\ 0 & \alpha & 5 \alpha \\ 0 & 0 & 5\end{array}\right]\). If \(|\mathrm{A}|^2=25\), then \(|\alpha|\) equals to
- A \(5^2\)
- B \(1\)
- C \(\frac{1}{5}\)
- D \(5\)
Answer & Solution
Correct Answer
(C) \(\frac{1}{5}\)
Step-by-step Solution
Detailed explanation
\(\begin{aligned} & A=\left[\begin{array}{ccc} 5 & 5 \alpha & \alpha \\ 0 & \alpha & 5 \alpha \\ 0 & 0 & 5 \end{array}\right] \\ & |A|=5(5 \alpha)-5 \alpha(0)+\alpha(0) \end{aligned}\)…
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