Inflection point

Blue is convex, red is an inflection point, and green is concave.

Point (0,0) is an undulation point.

An inflection point is a point on a curve where the curve changes from being concave (going up, then down) to convex (going down, then up), or the other way around.

An undulation point is like an inflection point but the type of curve doesn't change.

Inflection Point Media

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  Plot of y = x3 with an inflection point at (0,0), which is also a stationary point.