Polynomials

If b<0,and α,β are roots of the equation 2x^2 + 6x+b=0,and satisfy α/β + β/α<K.the the value of K?

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Math	Appears as
Remember to wrap math in `$` ... `$` or `\[` ... `\]` to ensure proper formatting.
`2 \times 3`	$2 \times 3$
`2^{34}`	$2^{34}$
`a_{i-1}`	$a_{i-1}$
`\frac{2}{3}`	$\frac{2}{3}$
`\sqrt{2}`	$\sqrt{2}$
`\sum_{i=1}^3`	$\sum_{i=1}^3$
`\sin \theta`	$\sin \theta$
`\boxed{123}`	$\boxed{123}$

Comments

$\frac{\alpha}{\beta} + \frac{\beta}{\alpha} \\ = \frac{\alpha^2 + \beta^2}{\alpha\beta} \\ = \frac{ (\alpha + \beta)^2 - 2\alpha\beta}{\alpha\beta} \\ = \frac{ (\frac{-6}{2})^2}{\frac{b}{2}} - 2 \\ = \frac{18}{b} - 2 < -2 (as b < 0) \\ \Rightarrow k = \fbox{-2}$

kushagraa aggarwal - 7 years, 9 months ago

(asb<0) wat does dis mean?

Abhishek Akella - 7 years, 9 months ago

I meant that $\frac{18}{b} < 0$ and hence $\frac{18}{b} - 2 < -2$

kushagraa aggarwal - 7 years, 9 months ago

@Kushagraa Aggarwal – kk thnxxx dude!!

Abhishek Akella - 7 years, 9 months ago

Math	Appears as
Remember to wrap math in `\(` ... `\)` or `\[` ... `\]` to ensure proper formatting.
`2 \times 3`	$2 \times 3$
`2^{34}`	$2^{34}$
`a_{i-1}`	$a_{i-1}$
`\frac{2}{3}`	$\frac{2}{3}$
`\sqrt{2}`	$\sqrt{2}$
`\sum_{i=1}^3`	$\sum_{i=1}^3$
`\sin \theta`	$\sin \theta$
`\boxed{123}`	$\boxed{123}$