Re: HSC 2013 4U Marathon
$The ellipse$ \ \ \ \frac{x^2}{a^2}+ \frac{y^2}{b^2}=1
$Has 2 points$ \ \ P(a\cos \theta, b\sin \theta) \ \ $and$ \ \ Q(a\cos \alpha, b\sin \alpha)
$The tangents at the points P and Q intersect at R at a right angle$
$i) Prove that the locus of R is a circle with...