Portal:Mathematics/Selected article/31

From Wikipedia, the free encyclopedia

< Previous Next >

edit  

Selected article 31
The graph of a real-valued quadratic function of a real variable x, is a parabola.
A quadratic equation is a polynomial equation of degree two. The general form is
ax^2+bx+c=0,\,\!

where a ≠ 0 (if a = 0, then the equation becomes a linear equation). The letters a, b, and c are called coefficients: the quadratic coefficient a is the coefficient of x2, the linear coefficient b is the coefficient of x, and c is the constant coefficient, also called the free term.

Quadratic equations are called quadratic because quadratus is Latin for "square"; in the leading term the variable is squared.

A quadratic equation has two (not necessarily distinct) solutions, which may be real or complex, given by the quadratic formula:

x = \frac{-b \pm \sqrt {b^2-4ac}}{2a},

These solutions are roots of the corresponding quadratic function

f(x) = ax^2+bx+c.\,
...Archive Image credit: Enoch Lau Read more...