University:
College
Course:
College Mathematics
Academic year:

2022
Views:

6

Pages:

3
Author:

anon

Mathematics: Reading coordinates off Cartesian Plane We are going to talk about coordinates. We want to plot values on a geometric plane. This might not make any sense right now, but sooner or later, you will get it. How can we express coordinates? We express coordinates in the form: (x,y) We plot the (x,y) point on what we call a Cartesian plane. The horizontal line is called the “x axis”. This is where the “x” value of the (x,y) coordinate system will go. The vertical line is called the “y axis”. This is where the “y” value of the (x,y) coordinate system will go. Now, what is the value of x and y? Of course, from the plane above, we don’t have any “values” so it’s impossible to assign a value for (x,y). However, if you look at the diagram below, it starts to make more sense: Now we have actual values for “x” and “y”. As you can see, the x values increase by 1 from the left and right, -3,-2,-1,0,1,2,3 etc. The same goes for the y values. However, when you plot points on the Cartesian plane, conventionally we always plot the x value before we plot the y value. To plot a coordinate (x,y) on the plane above, simply find the “x” coordinate (on the x axis), and then the “y” coordinate (on the y axis) For example: Plot the point (2,3) on the Cartesian Plane with a green dot. So our aim is to plot the point (2,3). Remember how coordinates go in the form (x,y). Well, in this case, x=2 and y=3. Let’s start off with the x-axis. The x axis value is 2, so on the Cartesian Plane below, I will draw a dot on the horizontal x-axis value 2. Now, let’s plot the y-value. The y-value here is 3, so on the Cartesian Plane below, I will draw a dot on the vertical y-axis value 3. Right now, the two values we plotted are independent of each other. We don’t want that. We want to make these values to become one point on the Cartesian Plane. If you draw a vertical line from where x=2 and a horizontal line from where y=3, you will realize that these 2 lines will intersect at a point, and if you look closely enough, you will realize that this intersection point is when x=2 and y=3, (2,3).