I'm having a problem with the following question. If anyone can help, that would be very much appreciated.
(1) Suppose that (a,b) is on the circle (x^2)+(y^2)=(r^2). Show that the line ax+by=(r^2) is tangent to the circle at (a,b).
PLEASE, IF ANYONE CAN HELP, I WOULD LOVE IT.
Thank you in advance