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.
... established the French colony in Canada; discovered the Great Lakes
William Clark, (1770-1838), with Meriwether Lewis led the first American expedition to reach the west ...