Graphing and Connecting Coordinate Points

Points can be plotted one at a time, or multiple points can be plotted from the same expression line using lists or a table. Get started with the video on the right, then dive deeper with the resources below and suggested articles to learn more.

 

Plotting and Connecting Points in the Graphing Calculator

Plotting Points

\left(-2,7\right). Screenshot.

To plot a point, enter your values as a coordinate pair (x,y):

\left(-3,2\right),\left(0,0\right),\left(2,1\right). Screenshot.

You can add multiple points on a line by separating each coordinate point with a comma.

Table showing the following coordinates: (1,2), (3,-2),(-1,2.5) and (2.3,\frac{1}{3}). Screenshot.

It is also possible to plot points using a table. Select the Add Item option in the expression list and select Table or you can type table into an expression line.

 

Point Options Menu

Long press the icon to the left of your expression to bring up the options menu for the plotted point. You will be able to show/hide the point, show/hide the label, make your point draggable, and adjust the opacity, width, font size, position and angle of the label.

If there are multiple points in an expression line or a table of points, there will also be an option to turn on lines to connect the points.

Points Option Menu. Screenshot.

 

Point Discontinuity

We do not automatically graph points of discontinuity. You can, however, use a table to help determine where a point of discontinuity is.

Graph of f\left(x\right)=\frac{x^{2}\left(x-2\right)}{\left(x-2\right)}, showing point of discontinuity at (2,4). Screenshot.

Once you have identified a point of discontinuity, you can plot it in a separate expression line and change the point from a closed circle to an open circle. To do so, long press the color icon next to the expression. The options menu will appear allowing you to select an open circle to plot the point of discontinuity. Explore each graph in this article by clicking on its image.

Point settings menu showing open circle selection. Screenshot.

 

Connecting Points

There are different ways to connect points with a line depending on the style and substance you're looking for.

When creating a table in Desmos, points can be connected by long pressing the icon next to the dependent column header. Choose from three different styles of lines.

GIF showing how to connect points from a table.

The polygon function can be used to connect points using a table or list of coordinates. In the example shown, a table is created containing the vertices of the polygon. On the next expression line we use the polygon function with the table headers x1, y1 as the two arguments needed to graph the polygon.

Connecting points using the polygon function. Screenshot.

Adding multiple points in the same expression line by separating each coordinate point with a comma will allow you to use the point option menu to connect points.

Connecting points using the points option menu. GIF

 

Plotting and Connecting Points Using the Geometry Toolbar

In the Desmos Geometry Tool there are different options available to plot and connect points.

Plotting Points

Start by selecting the point tool in the Geometry Toolbar and clicking the location you want your point on the graph paper. To change the color and add labeling, select a point, then select the More option from the Geometry Toolbar.

Plotting points in the Geometry tool using the Geometry toolbar. GIF

Connecting Points

Using the Geometry Toolbar, you can connect points by either creating a polygon with the polygon tool or a segment with the segment tool.

Connecting points in the Geometry tool using the polygon function. GIF

Plotting and Connecting Points in the 3D Calculator

In Desmos 3D, you can plot a point by entering the coordinates (x, y, z). Click and long-hold the color icon in the expression line to open the style menu for a graphed item to change the size and color of the point. Similar to the graphing calculator, try plotting points individually, on the same expression line separated by commas, or with variables defined by tables, sliders, or lists. If you are using a table, you will need to reference the table variables in a separate expression line to see the points from the table plotted in the cube.

Plotting point the point (2,2,2) and (1,1,1) in a single expression line to connect the points.  Using a table to plot and connect points. Screenshot.

You can also use the triangle function in the 3D Calculator to graph a triangle with 3 points. For example, try typing triangle((2,-1,0),(2,2,0),(0,0,2)).

Using the triangle function to plot and connect three points to form a triangle in 3d. Screenshot.

Learn More

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