P, Q and R are three points on the parabola y² = 4bx, and the ordinates of the points P, Q and R (in this order) are in geometric sequence. b is a constant.

The tangents drawn respectively at the points P and R intersect at the point T.

Is it always the case that QT is perpendicular to the tangent drawn at Q?

(In reply to I'm confused by Charlie)

"Rather than perpendicular to the tangent at Q, QT seems perpendicular to the axis of the parabola."

That's what I got.

Posted by Bractals on 2007-09-21 20:19:13