Consider the parabola with vertex and the directrix . Let P be the point where the parabola meets the line . If the normal to the parabola at intersects the parabola again at the point Q, then is equal to:
- (A)
- (B)
- (C)✓ Correct
- (D)
Answer: (C)
Solution
The vertex and directrix give and the equation . At , , so . The tangent slope there is , so the normal has slope : . Substituting the parabola, with , gives , so (point ) or (point ). Thus and
JEE Main · 2021 · 01 Sep 2021 · Shift 2 · Single correct option