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![\"Cartesian](\"https:\/\/www.aplustopper.com\/wp-content\/uploads\/2017\/04\/Cartesian-Coordinates-1.jpg\")
<\/p>\nThe French Mathematician and Philosopher Rene Descartes first published his book La Geometric in 1637 in which he used algebra in the study of geometry. This he did by representing points in a plane by ordered pairs of real numbers, called Cartesian coordinates (named after Rene Descartes). In this section, we shall see how points in a plane are represented by the ordered pair of real numbers.<\/p>\n
Let X’OX and Y’OY be two mutually perpendicular lines through a point O in the plane of a graph paper as shown in Fig. 11.1. The line X’OX is called the r-axis or axis of x the line Y’OY is known as the y-axis or axis of y, and the two lines X’OX and Y’OY taken together are called the coordinate axes or the axes of coordinates. The point O is called the origin.
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In Fig. 11.1, the coordinate axes X’OX and Y’OY divide the plane of the graph paper into four regions XOY, X’OY, X’OY’ and Y’OX. These four regions are called the quadrants. The regions XOY, X’OY, X’OY’ and Y’OX are known as the first, the second, the third and the fourth quadrants respectively.<\/p>\n