is any tangent to the parabola . The ordinate of the point on this tangent such that the other tangent from it which is perpendicular to it is |

is any tangent to the parabola . The ordinate of the point on this tangent such that the other tangent from it which is perpendicular to it is |

1 Answer

127 votes

Clearly is the point of intersection of two perpendicular tangents to the parabola or Hence, must lie on the directrix or hence the point is |

127 votes

127