Cartesian Coordinate System 

Cartesian Coordinate system developed in seventeenth century by Rene Descartes the great French philosopher and mathematician.

Cartesian Coordinate system, also called rectangular Coordinate system and used to position of points on a two dimensional or three dimensional plane. 

Let’s briefly learn about Cartesian Coordinate system.

          Cartesian Coordinate plane

The plane is called Cartesian plane or Coordinate plane or the XY  plane.

A Cartesian Coordinate plane is defined by two intersecting number lines at a 90 degree angle (perpendicular number lines), and the point where they intersect is known as origin.

Simply the Cartesian Coordinate plane is just two number lines, where one is horizontal and other is vertical and both form right angle with each other. 

When the position of an object or a point, locate in a plane we require two perpendicular lines.

                              Point

When we want to plot a point, we need two things,

1. A point
2. A plane

The location of a point, in a plane is represented by it’s coordinates. 

                 X and Y Coordinates

The “X coordinate” is always comes first number in the pair. 

The “Y coordinate” is always comes second number in the pair.

Ordered pair- Points on the Cartesian plane is known as Ordered pair.

X and Y axes

We have already studied about number line. we know that zero is always in the center of the number line, right of the number line, comes positive numbers, and the left of the number line, comes negative numbers.

First we take two number lines calling them XX’ and YY’.

One of them is horizontal and the other is vertical,

The horizontal line is called X-axis and the vertical line is called Y-axis. 

 The horizontal line is called X-axis. 

   The vertical line is called Y-axis. 

Now combine them, in such a way that the two lines intersect each other at their zero or origins.

                                     Origin

The point where the lines XX’ and YY’ are intersect is called Origin, whose coordinates are (0,0) and origin is denoted by O.

All positions are measured from the origin. 

OX and OY are called positive directions of respectively X-axis and Y-axis.

OX’ and OY’ are called negative directions of respectively X-axis and Y-axis.

We see that the two axes X and Y divided the plane into four sections.

The plural of axis is axes.

These four sections are called the Quadrants (one- fourth section).

The quadrants are labelled with Roman numbers as,

First quadrants – I

Second quadrants – II

Third quadrants – III

Fourth quadrants – IV

The plane is called Cartesian plane or Coordinate plane or the XY plane.