Well, check it in the original equation! If then so
On the other hand, if , is still but now we have which is not 1- but your original equation allowed " ".
Actually, your original equation had which is equivalent to , a circle with center at (0,0) and radius 2. The tangent line will have slope 1 where that circle intersects the line with slope -1, y= -x. If y= -x, and so and but notice that the tangent line has slope 1 at and . The points and also are on that circle, have but the tangent lines do not have slope 1 there.
You know, you really did not need to open a new thread just to continue
http://www.mathhelpforum.com/math-he...erivative.html
By the way, what is a "geographic" derivative?
I meant geometric derivative...thats what the book I'm self studying from calls it, not my title. Sorry about the typo.By the way, what is a "geographic" derivative?
Thank you for the help. I haven't studied circles much, so equations like that are semi-foreign to me.