JEE Main2018MathematicsStraight LinesActual
The locus of the point of intersection of the lines 2 x - y + 4 2 k = 0 and 2 k x + k y - 4 2 = 0 ( k is any non-zero real parameter) is
Options
- Aan ellipse whose eccentricity is 1 3
- Ba hyperbola whose eccentricity is 3
- Ca hyperbola with length of its transverse axis 8 2
- Dan ellipse with length of its major axis 8 2
Correct answer
C. a hyperbola with length of its transverse axis 8 2
Step-by-step solution
Given equation of lines are 2 x - y + 4 2 k = 0           . . . 1 and 2 k x + k y - 4 2 = 0             . . . 2 Eliminating k from 1 and 2 , ⇒ 2 x + y 2 x - y - 4 2 = 4 2 ⇒ 2 x 2 - y 2 = - 32 ⇒ y 2 32 - x 2 16 = 1 , which is a hyperbola. ⇒ e = 1 + 16 32 = 3 2 and length of transverse axis = 8 2 .