Identify Coordinates

Learning outcomes :

    1.      Identify the x-axis, y-axis and the origin in the Cartesian Plane.

    In the Cartesian Plane , the horizontal number line is called the x-axis whereas the vertical number line is     called the y-axis. The intersection point of the  x-axis and the y-axis is known as the origin is usually           represented with the letter 0.

Horizontal number line is called the x-axis

 Vartical number line is called the y-axis

Show the origin 

Identify positive and negative at x-axis and y-axis

Vedio for Coordinate Plane

                                           

      2.      Plotting point and stating the coordinates of the points.

      The  position of any point Cartesian Plane can be determined by its distance from each of the axis .

      For example if  point P in the Cartesian Plane is located by an ordered pair(a,b), then

                               I.            The x-coordinate of P is a and the distance of P from the y-axis is a units.

                             II.            The y-coordinate of P is b and the distance of P from the x-axis is b units.

video identify plotting points

example:

  Plot the following points on a Cartesian plane.

1. A(2, 3)
2. B(- 3, 2)   
3. C(- 4,- 3)   
4. D(6, - 4)

 solution

1. 
   

2. 

3. 

4. 

      3.      Plotting point and stating the distances of the points from the y-axis and x-axis.

      Example.

The coordinate of P are (4,3)

     4.      Stating the coordinates of points in a Cartesian plane.

     The Cartesian plane has four quadrants.

     In quadrant  1, the coordinates of any point are positive.

     In quadrant  2, the x-coordinate of any point is negative

     In quadrant 3, the coordinates of any point are negative.

     In quadrant 4, the y-coordinates of any point are negative.

  

Introduction Coordination

What are coordinates?

To introduce the idea, consider the grid on the right. The columns of the grid are lettered A,B,C etc. The rows are numbered 1,2,3 etc from the top. We can see that the X is in box D3; that is, column D, row 3.

D and 3 are called the coordinates of the box. It has two parts: the row and the column. There are many boxes in each row and many boxes in each column. But by having both we can find one single box, where the row and column intersect.

The Coordinate Plane

In coordinate geometry, points are placed on the "coordinate plane" as shown below. It has two scales - one running across the plane called the "x axis" and another a right angles to it called the y axis. (These can be thought of as similar to the column and row in the paragraph above.) The point where the axes cross is called the origin and is where both x and y are zero.

On the x-axis, values to the right are positive and those to the left are negative.
On the y-axis, values above the origin are positive and those below are negative.

A point's location on the plane is given by two numbers,the first tells where it is on the x-axis and the second which tells where it is on the y-axis. Together, they define a single, unique position on the plane. So in the diagram above, the point A has an x value of 20 and a y value of 15. These are the coordinates of the point A, sometimes referred to as its "rectangular coordinates". Note that the order is important; the x coordinate is always the first one of the pair.