The lines represented b the equations $23 x^2-48 x y+3 y^2=0$ and $2 x+3 y+4=0$ form

The lines represented b the equations $23 x^2-48 x y+3 y^2=0$ and $2 x+3 y+4=0$ form
  1. an isosceles triangle
  2. an equilateral triangle
  3. a right angled triangle
  4. a scalene triangle

Solution

(c) We have, $ \begin{aligned} & 23 x^2-48 x y+3 y^2=0 \\ & \Rightarrow \quad 3 y^2-48 x y+23 x^2=0 \\ & \text { Here, } \quad M_1+M_2=16 \\ & \text { and } M_1 M_2=\frac{23}{3} \\ & \therefore \quad m_1-m_2=\sqrt{\left(m_1+m_2\right)^2-4\left(m_1 m_2\right)} \\ & =\sqrt{(16)^2-4 \times \frac{23}{3}}=\sqrt{256-\frac{92}{3}}=\sqrt{\frac{768-92}{3}}=\frac{26}{\sqrt{3}} \\ & \therefore \quad m_1=8+\frac{13}{\sqrt{3}} \text { and } m_2=8-\frac{13}{\sqrt{3}} \\ & \tan \theta=\left|\frac{m_1-m_2}{1+m_1 m_2}\right|=\left|\frac{\frac{26}{\sqrt{3}}}{1+\frac{23}{3}}\right|=\sqrt{3} \\ & \end{aligned} $ We know that, than $60^{\circ}$ So, $ \theta=60^{\circ} $ Slope of line $2 x+3 y+4=0$ is $-\frac{2}{3}$ Angle between line of slope $8+\frac{13}{\sqrt{3}}$ and $-\frac{2}{3}$ is $ \begin{aligned} \tan \alpha & =\frac{8+\frac{13}{\sqrt{3}}+\frac{2}{3}}{1+\left(8+\frac{13}{\sqrt{3}}\right)\left(\frac{2}{3}\right)}=\sqrt{3} \\ \therefore \quad \theta & =60^{\circ} \\ \Rightarrow \quad \alpha & =60^{\circ} \end{aligned} $ Hence, line from a equilateral triangle

Asked in: AP EAMCET 2018 (22 Apr Shift 1)

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