A quadratic function is a function of the form <math>f(x)=ax^2+bx+c</math>, where a is nonzero.
In the case where the domain and codomain are R (the real numbers), the graph of such a function is a parabola.
... of its grammar and lexicon (see History below) it turned into a classical language of strict esthetic rules and gave rise to considerable literature of drama in poetry and ...