Intuitively, the [url=https://en.wikipedia.org/wiki/Curvature]curvature[/url] is the amount by which a [url=https://en.wikipedia.org/wiki/Curve]curve[/url] deviates from being a [url=https://en.wikipedia.org/wiki/Straight_line]straight line[/url].[br]For curves, the canonical example is that of a [url=https://en.wikipedia.org/wiki/Circle]circle[/url], which has a curvature equal to the [url=https://en.wikipedia.org/wiki/Multiplicative_inverse]reciprocal[/url] of its [url=https://en.wikipedia.org/wiki/Radius]radius[/url]. Smaller circles bend more sharply, and hence have higher curvature. The curvature [i]at a point[/i] of a [url=https://en.wikipedia.org/wiki/Differentiable_curve]differentiable curve[/url], is the curvature of its [url=https://en.wikipedia.org/wiki/Osculating_circle]osculating circle[/url], that is the circle that best approximates the curve near this point. The curvature of a straight line is zero. [br][br][url=https://en.wikipedia.org/wiki/Cycloid]Cykloida[/url] jako trajektorie při odvalování kružnice po přímce. [br]Průběh křivosti je znázorněn stopou zelených bodů na normále sestrojených ve vzdálenosti k.

Změnou polohy tvořícího bodu A obdržíme zkrácenou, prostou nebo prodlouženou cykloidu. [br]Stopy smažete změnou měřítka grafického okna (kolečko myši).