Labels

By adding a point to the expression list, you'll automatically have the option to add a label. Enabling the checkbox without adding text will automatically show the coordinates of the point on the graph paper.

    


To create a text label, make sure the "Show Label" checkbox is enabled and type in the text of your choice. The graph paper will automatically update. It's also possible to create labels on movable points

 

Dynamic Labels

If a parameter is already defined in the calculator, then the value of that variable can be used to create dynamic labeling. For example, if m and b are defined in the calculator, then typing ${m} and/or ${b} in any point label text areas will display the numerical values of m and b. The label will automatically update as the value of m or b changes and can be used with text to great effect. Below, we've used y = ${m}x + ${b} as a point label in order to display the equation of the line in slope-intercept form as the sliders are moved. 

 

It's also possible to add formatted math text using back-ticks. This can be combined with dynamic labels to display equations on the graph paper.

 

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17 Comments

  • 0
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    Michael Solyom

    Not sure if this is related or not, but since this has been implemented I've noticed a problem with intersecting lines: if I click on the intersection of two lines Desmos will let me know the coordinates in the "old" style black and white label, but if I change a slider that moves either line it loses the label -- it used to automatically update and move along with my changes.

    Here's an example: https://www.desmos.com/calculator/t5tckrsxle

    Where the lines intersect is pretty important when I'm building assignments for my students, and to solve for all seven intersections algebraically to build a "new" style label for each seems a bit excessive to me.

    Is this an issue you're aware of?

    Thanks!

  • 7
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    Bernard Gilroy

    I absolutely love the label feature.  But I'm sad that, as far as I can tell, the labels will not show up on images generated via the share button.  I prefer using that to taking screenshots, but I don't know how to make point labels appear in the png image.

  • 5
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    Filippo Alberto Edoardo Nuccio

    I have the same problem as Bernard: the feature is great, but it would be awsome to be able to export these labels when creating a png image.

  • 0
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    Joshua Begay

    This is an awesome feature! It would be helpful if the coordinate point could be minimized or made invisible. That way we could place a label near features that don't necessarily have a point.

     

    --- Nevermind! Figured it out.

    Edited by Joshua Begay
  • 0
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    WeThotUWasAToad

    Joshua, I have exactly the same question (ie hiding the actual point so only the label is displayed). I'm glad you "figured it out" but can you explain the solution? Thanks.

     

     

  • 0
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    Joshua Begay

    WeThotUWasAToad,

    Add your label then un-select the point by clicking on the colored circle (circle in red). This will turn off the point but leave the label. The label will move around depending on the zoom.

    p.s. DO NOT SEEK THE TREASURE!

    Edited by Joshua Begay
  • 1
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    Williamh22114065

    How do you label a function?

     

  • 1
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    Josh Hill

    How do you label a line?

  • 1
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    Jimbo iscool

    Josh Hill, I don't think there is a way for the label to follow the screen, but I came up with this method so you can move the label. (Excuse the variables, I already had stuff on this graph and was too lazy to make a new one.)

  • 1
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    Royi

    Why is the Math expression in Label is parsed so badly?

    Is there to make it look the expressions themselves?

    Thank You.

  • 1
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    Kendra Lockman

    Hi, Royi.

    You can include formatted math in labels with LaTeX. So for example to label something x^2 and have it come out as math, type in `x^2` (using the forward-quote, next to the 1 on most keyboards).

    It seems that, for now at least, you can't combine plain text with math formatting in the same label. So you wouldn't be able to create the label  This line is `x^2`

  • 0
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    Royi

    @Kendra,

    Could you show an example?

    Thank You.

  • 1
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    Kendra Lockman
  • 0
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    John Bennett

    Is it possible to have a label choose between two text values? For example, have some moveable points that could be on either the x- or y-axis. The non-zero coordinate is c. So when the point is on the x-axis, I would like the label to show (c, 0) and when it is on the y-axis, (0,c).

    https://www.desmos.com/calculator/2gpuibeyaj

    This file is what I'm working on. The foci of the ellipse can move between the x- and y-axes depending on which of a and b are larger. I would like the labels to adjust when the foci change axes.

  • 0
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    Kendra Lockman

    Hi, John.

    I would create two points, one for each instance, and use conditionals to only show that point sometimes. Here's what I mean with your graph.

    https://www.desmos.com/calculator/sv3sk5dzgi

     

    I've done this before to create On/Off switches, where I have one point labeled On, which only shows when the point is in the on position, and another point labeled Off, which only shows when the point is in the off position. If I color them the same, then they look like the same point. Like so.

  • 0
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    John Bennett

    That's awesome. I didn't realize you could condition coordinates like that.

  • 0
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    Kendra Lockman

    Yeah, it doesn't feel intuitive to me, but it makes sense since you can have calculations inside coordinates. I think I saw it a few times in other people's graphs before it sunk in for graphs I created myself.

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