Start Free Mock LoginAlready registered? Login here

Mathematics - Parabola Question with Solution | TestHub

MathematicsParabolaNormal to ParabolaMedium2 minQB

MathematicsMediumsingle choice

If $(3 m_{i}^{2}, - 6 m_{i})$ are the feet of normals from $(1, 2)$ to $y^{2} = 12 x$ , find $\sum_{i} 1/ m_{i}$ .

Options:

Answer:

Solution:

The normal is $y = m x - 6 m - 3 m^{3}$ . Through $(1, 2)$ it gives $3 m^{3} + 5 m + 2 = 0$ . Vieta yields $(m_{1} m_{2} + m_{2} m_{3} +$ $m_{3} m_{1}) / (m_{1} m_{2} m_{3}) = - 5/2$ .

Stream:JEESubject:MathematicsTopic:ParabolaSubtopic:Normal to Parabola

⏱ 2mℹ️ Source: QB

Doubts & Discussion

Loading discussions...