Points of Inflexion
A point of inflection is a point on a curve where the curvature defined by
changes from being positive to negative or vice versa, so that
but
A point of inflexion is not necessarily a stationary point, where
– if in addition
it is called a stationary point of inflexion.
Example:
and
so the graph has a point of inflexion at
It is not a stationary point of inflexion because when
