Question

implicit differentiation, please help!

Answer 1

Okay, here's the question: show using implicit differentiation, that any tangent line at a point P to a circle with radius "r" and center at origin O is perpendicular to the radius OP.

Answer 2

I know the equation of the circle will be \[x^2+y^2=r^2\] and that I need to prove that the product of the two derivatives equals -1, but I tried doing it and got really confused.