The graph of a quadratic equation forms a parabola. The technique of graphing as it is practiced today is based on the work of René Descartes. (Image credit: Robert Coolman) ...

The conventional linear/quadratic/Gaussian assumptions are modified in that minimisation of the expectation of cost G defined by (2) is replaced by minimisation of the criterion function (5). The ...

A quadratic equation is drawn as a curve on a set of axes. This type of curve is called a parabola and it is symmetrical. To draw the graph we need coordinates.

Hirofumi Wakaki, Comparison of Linear and Quadratic Discriminant Functions, Biometrika, Vol. 77, No. 1 (Mar., 1990), pp. 227-229 ...

does not contain any powers higher than 1. A quadratic equation contains a variable that's highest power is 2. For example: y = x + 3 is a linear equation and y = x 2 + 3 x is a quadratic equation.