Circle of Curvature and Radius of Curvature
Introduction
Circle of curvature is a circle that "fit" the curve at a point.
If the curve is turning sharply, the radius of curvature is small and
if the curve is turning slowly, the radius of curvature is large.
Applet 1 shows change of the radius of curvature on y=cos x.
Applet 2 shows a method to find the circle of a curvature at (0,1)
on y=cos x.
Applet 1
Applet 2