Differentiation

Concave Upwards and Concave Downwards Curves
Relates to the second derivative
Concave Upwards:

Stationary Points of Inflection

Non-Stationary Points of Inflection

Some points of inflection are NOT stationary (ie dy/dx =/ 0 )
Either on an increasing function or a decreasing function
Investigate both sides of the point to determine type of function (increasing
or decreasing)