In mathematics, a polynomial equation of second degree (that is, an equation containing as its highest power the square of a variable, such as x 2 ).
A plane figure formed by four intersecting lines. A simple quadrilateral is a polygon with four sides. A complete quadrilateral ( see diagram) is the
Quantum theory of the interactions of charged particles with the electromagnetic field . It describes the interactions of light with matter as well as
In statistics, any one of the three values that divide data into four equal parts. They comprise the lower quartile , below which lies the lowest 25%