AP EAMCET2005MathematicsParabola
The line among the following which touches the parabola y^2=4 a x , is
Options
- Ax+m y+a m^3=0
- Bx-m y+a m^2=0
- Cx+m y-a m^2=0
- Dy+m x+a m^2=0
Correct answer
B. x-m y+a m^2=0
Step-by-step solution
Given equation of parabola is y^2=4 a x Let the equation of line be y=m x+c If this line touches the parabola, then aligned & c= a m & y=m x+ a m m y=m^2 x+a & replacing m by 1 m , we get & m y=x+a m^2 & x-m y+a m^2=0 aligned