Let $\alpha$ and $\beta$ be two real roots of the equation
(k + 1)tan2x - $\sqrt 2$ . $\lambda$tanx = (1 - k), where k($\ne$ - 1)
and $\lambda$ are real numbers. if tan2 ($\alpha$ + $\beta$) = 50, then a value of $\lambda$ is:
Solution
Let tan$\alpha$ and tan$\beta$ are the roots of
<br><br>(k + 1)tan<sup>2</sup>x - $\sqrt 2$ . $\lambda$tanx - (1 - k) = 0
<br><br>$\therefore$ tan$\alpha$ + tan$\beta$ = ${{\sqrt 2 \lambda } \over {k + 1}}$
<br><br>and an$\alpha$.tan$\beta$ = ${{k - 1} \over {k + 1}}$
<br><br>Now tan($\alpha$ + $\beta$)
<br><br>= ${{\tan \alpha + \tan \beta } \over {1 - \tan \alpha \tan \beta }}$
<br><br>= ${{{{\lambda \sqrt 2 } \over {k + 1}}} \over {1 - {{k - 1} \over {k + 1}}}}$
<br><br>= ${{{\lambda \sqrt 2 } \over 2}}$ = ${{\lambda \over {\sqrt 2 }}}$
<br><br>Given ${{{{\lambda ^2}} \over 2}}$ = 50
<br><br>$\Rightarrow$ $\lambda$ = 10
About this question
Subject: Mathematics · Chapter: Complex Numbers and Quadratic Equations · Topic: Complex Numbers and Argand Plane
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