# Thread: curvature of planar curves

1. ## curvature of planar curves

Ok, so, i have a serious problem and i need help, since english is not my mother language i'm not sure if this is the right name of the problem..

i have function in implicit shape y^2 = x^2 * ((4+x)/(4-x))

and for the curvature there is formula

and i don't understand how to get to those parameters

help pls

2. I guess then the question is "what is F". That is, what does the function F represent in that formula? Are the subscripts indices or derivatives? And if they are derivatives, what do F' and F'' mean?

3. Originally Posted by HallsofIvy
I guess then the question is "what is F". That is, what does the function F represent in that formula? Are the subscripts indices or derivatives? And if they are derivatives, what do F' and F'' mean?

well that is what i wonder too..I got that formula from Bronstein's handbook of mathematics, as a formula for curvature, but i don't really understand anything about it =(((

4. I found another formula

But this doesn't help me much either cause i really don't understand this stuff..

5. anyone??

anything??