These are named after the French mathematician Descartes who used these for studying analytical geometry. This gives a method of defining the position of a point by its distance from a fixed point O (origin) into the direction of two or more straight lines.

In a plane, two straight lines are called the X-axis and Y-axis forms the basis of the two-dimensional coordinates system. The point of intersection of the two axes is called the O (origin).

An imaginary grid is formed by lines parallel to the axes and unit distance apart. For example, the point (5, 3) is the point where the line parallel to Y-axis, meets the line parallel to X-axis three-unit away from X-axis.

The position of a point in space can be determined by three measurements with respect to three concurrents lines called axes of coordinate. These axes form a frame of references and the point of concurrency is the O (origin) of coordinates. These axes are referred to as X-axis, Y-axis, and Z-axis, and the coordinates of a point are (x, y, z) as shown in the figure.

The axes are usually taken as mutually perpendicular and hence are called rectangular axes and the coordinates are called rectangular coordinates. When the axis is not at right angles these are called the oblique axis.

**Cartesian equation :**

An equation of a configuration in Cartesian coordinates. See coordinates.

**Cartesian Product :**

The set of all ordered pairs of elements (a, b) where a belongs to A and b belongs to B is called cartesian

product of two sets A and B which is written as A x B.