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Home  >>  JEEMAIN and AIPMT  >>  Mathematics  >>  Class12  >>  Matrices
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Let $A=\begin{vmatrix}5 &5\alpha&\alpha\\0&\alpha&5\alpha\\0&0&5\end{vmatrix}$ if $\mid A^2\mid=25$ then $\alpha$ equals

$(a)\;\large\frac{1}{5}$$\qquad(b)\;5\qquad(c)\;5^2\qquad(d)\;1$

Can you answer this question?
 
 

1 Answer

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$\mid A^2\mid=25$
$\Rightarrow (25\alpha)^2=25$
$\mid \alpha\mid=\large\frac{1}{5}$
Hence (a) is the correct answer.
answered Nov 21, 2013 by sreemathi.v
 

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