The signed curvature formula for a planar parametric curve is given in
(2.25). Due to the regularity condition, a
necessary condition to determine inflection points is
(8.8)
An inflection point on a planar curve is shown in Fig.
8.7, marked by
.
The curvature
of a space curve is given in
(2.26). The formula can be expressed as
(8.9)
Since we are assuming a regular curve, a condition to determine a
point on a curve, where the curvature
vanishes, is [57]
(8.10)
or
(8.11)
Curvature vanishing points on a space curve
are shown in Fig.
8.8, marked by
.