The system used for describing the position of a point in a plane with reference to two mutually perpendicular lines is called cartesian or rectangular coordinate system.
Coordinate axes: Let us draw a horizontal line on a graph paper and draw a vertical line intersecting the horizontal line. The horizontal line is called x -axis and vertical line is called y -axis. The two lines taken together are called coordinate axes.
Origin: The point of intersection of x-axis and y -axis are called origin.
Quadrant: The coordinate axis divide the plane of graph paper into 4-regions called quadrant. Coordinate of a point: Let A(x, y) be the point in a plane.
x=distance of point from y-axis.
y=distance of point from x-axis.
Convention of sign:
I quadrant →x > 0, y > 0
II quadrant →x < 0, y > 0
III quadrant →x < 0, y < 0
IV quadrant →x > 0, y < 0