If the value of real number $a>0$ for which $x^2-5 a x+1=0$ and $x^2-a x-5=0$
have a common real root is $\frac{3}{\sqrt{2 \beta}}$ then $\beta$ is equal to ___________.
Answer (integer)
13
Solution
<p>${x^2} - 5\alpha x + 1 = 0$ ..... (1)</p>
<p>${x^2} - \alpha x - 5 = 0$ ...... (2)</p>
<p>have a common root.</p>
<p>Subtracting (1) with (2) we'll get $x = {6 \over {4\alpha }}$</p>
<p>Substituting in (1)</p>
<p>${{36} \over {16{\alpha ^2}}} - {{30} \over 4} + 1 = 0$</p>
<p>$\Rightarrow {\alpha ^2} = {9 \over {26}}$</p>
<p>$\alpha = {3 \over {\sqrt {2 \times 13} }}$</p>
<p>$\therefore$ $\beta = 13$</p>
About this question
Subject: Mathematics · Chapter: Complex Numbers and Quadratic Equations · Topic: Complex Numbers and Argand Plane
This question is part of PrepWiser's free JEE Main question bank. 223 more solved questions on Complex Numbers and Quadratic Equations are available — start with the harder ones if your accuracy is >70%.