<P> One way is geometrical . It is natural to define the curvature of a straight line to be constantly zero . The curvature of a circle of radius R should be large if R is small and small if R is large . Thus the curvature of a circle is defined to be the reciprocal of the radius : </P>
<P> One way is geometrical . It is natural to define the curvature of a straight line to be constantly zero . The curvature of a circle of radius R should be large if R is small and small if R is large . Thus the curvature of a circle is defined to be the reciprocal of the radius : </P>
curvature of a circle of radius r is given by
curvature of a circle of radius r is given by
the reciprocal of the radius
the reciprocal of the radius