JEE Main2006MathematicsParabolaActual
The locus of the vertices of the family of parabolas y= a^3 x^2 3 + a^2 x 2 -2 a is
Options
- Ax y= 105 64
- Bx y= 3 4
- Cx y= 35 16
- Dx y= 64 105
Correct answer
A. x y= 105 64
Step-by-step solution
Parabola: y= a^3 x^2 3 + a^2 x 2 -2 a Vertex: ( , ) aligned & = -a^2 / 2 2 a^3 / 3 =- 3 4 a , = - ( a^4 4 +4 a^3 3 2 a ) 4 a^3 3 =- - ( 1 4 + 8 3 ) a^4 4 3 a^3 & =- 35 12 a 4 3=- 35 16 a & =- 3 4 a (- 35 16 ) a= 105 64 . aligned