InterviewSolution
Saved Bookmarks
| 1. |
If the line lx + my + n = 0 touches the parabola y2 = 4ax, then(a) In = am(b) In2 = am2(c) l2n = am2(d) In = am2 |
|
Answer» Correct option (D) ln = am2 Explanation : Suppose lx + my + n = 0 touches the parabola y2 = 4ax at (at2, 2at). However, ty = x + at2 is the equation of the tangent at (at2, 2at). Therefore l/1 = m/-t = n/at2 ⇒ - m/l = t = -n/ma ⇒ am2 = ln |
|