Graphs The Plot Area Carmelo Ellul We use graph paper for plotting line graphs and curves. y The x-axis and the y-axis divide the plot area into 4 QUADRANTS. The x-axis and the y-axis The x-axis 2nd Quadrant 1st Quadrant A powerpoint presentation by Carmelo Ellul Head of Department (Mathematics) The x-axis and the y-axis intersect at the O, the ORIGIN. x O 3rd Quadrant 4th Quadrant

Graphs The Plot Area The x-axis is numbered at equal intervals y The y-axis is similarly divided into equal intervals 4 3 Each interval On each axis is called a UNIT. 2 1 cm represents each UNIT on the x-axis. 1 2 cm represent each UNIT on the y-axis. -5 -4 -3 -2 -1 1 2 3 -1 -2

Graphs The Plot Area The x-RANGE is the limits within which the x-axis lies. x y O 1 2 3 -1 -2 -3 -4 -5 4 This is written as: x-range is from -5 to 3 or x lies between -5 and 3 or -5  x  3 y-range Similarly the y-range Similarly the y-range can be written as. y-range is from -2 to 4 or y lies between -2 and 4 or -2  y  4 x-range

Graphs The Plot Area The position of a POINT on the plot area is described by two numbers known as the: x-coordinate y-coordinate x y O 1 2 3 -1 -2 -3 -4 -5 4 A 3 on the y-coordinate A(-2, 3) is the point in line with -2 on the x-coordinate Mark the point with a  (other valid markings are + or ) Label the point A

Graphs RESTART The Plot Area END SHOW The position of a POINT on the plot area is described by two numbers known as the: x-coordinate y-coordinate x y O 1 2 3 -1 -2 -3 -4 -5 4 A -2 on the x-coordinate A(-2, 3) is the point in line with 3 on the y-coordinate Mark the point with a  (other valid markings are + or ) Label the point A