The auxiliary equation of the lines passing through the origin and having slopes $\sqrt{3}+1$ and…

The auxiliary equation of the lines passing through the origin and having slopes $\sqrt{3}+1$ and $\sqrt{3}-1$ is
  1. $m^{2}-2 \sqrt{3} m+2=0$
  2. $m^{2}-2 \sqrt{3} m-2=0$
  3. $m^{2}+2 \sqrt{3} m-2=0$
  4. $m^{2}+2 \sqrt{3} m+2=0$

Solution

Equations of required lines are $y=(\sqrt{3}+1) x \text { and } y=(\sqrt{3}-1) x$ $\therefore$ their joint equation is $[(\sqrt{3}+1) x-y][(\sqrt{3}-1) x-y]=0$ $\therefore 2 x^{2}-2 \sqrt{3} x y+y^{2}=0$ Dividing both sides by $x^{2}$, we get $\begin{aligned} \left(\frac{y}{x}\right)^{2}-2 \sqrt{3} \frac{y}{x}+2 &=0 \\ \therefore m^{2}-2 \sqrt{3} m+2 &=0 \end{aligned}$

Asked in: MHT CET 2020 (12 Oct Shift 1)

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