If $α$ and $β$ are the zeros of the quadratic polynomial $f(x)\ =\ 6x^2\ +\ x\ –\ 2$, find the value of $\frac{α}{β}\ +\ \frac{β}{α}$.


Given:

$α$ and $β$ are the zeros of the quadratic polynomial $f(x)\ =\ 6x^2\ +\ x\ –\ 2$.


To do:

Here, we have to find the value of $\frac{α}{β}\ +\ \frac{β}{α}$.


Solution: â€ŠWe know that, 

The standard form of a quadratic equation is $ax^2+bx+c=0$, where a, b and c are

constants and $a≠0$

Comparing the given equation with the standard form of a quadratic equation, 

$a=6$, $b=1$ and $c=-2$

Sum of the roots $= α+β = \frac{-b}{a} = \frac{-1}{6} = -\frac{1}{6}$.

Product of the roots $= αβ = \frac{c}{a} = \frac{-2}{6} = -\frac{1}{3}$.

Therefore,

$\frac{α}{β} +\frac{β}{α}=\frac{(α^2 +β^2)}{αβ}$

$=\frac{(α+β)^2-2αβ}{αβ}$

$ \begin{array}{l}
=\frac{\left( -\frac{1}{6}\right)^{2} -2\left( -\frac{1}{3}\right)}{-\frac{1}{3}}\\
\\
=\frac{\frac{1}{36} +\frac{2}{3}}{-\frac{1}{3}}\\
\\
=\frac{( 1+2\times 12)}{36} \times \frac{-3}{1}\\
\\
=\frac{-( 1+24)}{12}\\
\\
=\frac{-25}{12}
\end{array}$

The value of $\frac{α}{β}\ +\ \frac{β}{α}$ is $\frac{-25}{12}$.

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Updated on: 10-Oct-2022

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