Introduction to Coordinate Geometry

The Cartesian plane is one of the greatest inventions in mathematics.  Had Rene Descartes not invented the rectangular coordinate system, calculus would not have progressed immensely as we are using it in our time.

The Number Line

The coordinate system was derived from the correspondence between the real numbers and the points on number line.  Each point on the number  line corresponds to a real number and each real number corresponds to a point on the number line. The number line represents the ‘entirety’ of the real numbers.  By convention, the number line is a horizontal line where the negative numbers are placed on the left of 0, and  the positive numbers on the right. » Read more