1. The problem statement, all variables and given/known data Show that the tangent to the ellipse ax^2+by^2=1 at the point (h,k) has equation ahx+bky=1 Hence, deduce that the chord of contact of tangents from the point (m,n) to the ellipse ax^2+by^2=1 has equation amx+bny=1 2. Relevant equations 3. The attempt at a solution I managed to prove the first part but am having problem with the second part. Of course, it can be done by evaluating the gradient of tangent of the ellipse and use the straight line formulas to prove that. But i am not sure how to DEDUCE that from what i got from the first part.