Q128 / 225 · JEE Main 2004 · Mathematics

If $a \neq 0$ and the line $2 b x+3 c y+4 d=0$ passes through the points of intersection of the parabolas $y^2=4 a x$ and $x^2=4 a y$, then

  • Correct answer
    A
    $d^2+(2 b+3 c)^2=0$
  • B
    $d^2+(3 b+2 c)^2=0$
  • C
    $d^2+(2 b-3 c)^2=0$
  • D
    $d^2+(3 b-2 c)^2=0$

Solution

Points of intersection of given parabolas are $(0,0)$ and $(4 a, 4 a)$ $\Rightarrow$ equation of line passing through these points is $y=x$ On comparing this line with the given line $2 b x+3 c y+4 d=0$, we get $d=0$ and $2 b+3 c=0 \Rightarrow(2 b+3 c)^2+d^2=0$

Hence, the correct answer is option: 'A'.

More Parabola Questions