1 (edited by ArcherSam 2011-08-31 19:05:27)

Topic: Graphing Real Number Lines

Ivan Johansen

In: Edit > Axes > Axes style. Could you add a radio button that would allow you to hide the y-axis, and add an arrow pointing left onto the left endpoint of the x-axis?


Post's attachments

Attachment icon Graphing Real Number Lines.jpg 26.47 kb, 352 downloads since 2011-08-31 

Re: Graphing Real Number Lines

I will consider it.
If you use the latest beta version of Graph and has Python 3.2 installed you will be able to press F11 to get a Python interpreter where you can write the following to hide the y-axis and show an arrow on the left side of the x-axis:


Re: Graphing Real Number Lines


Re: Graphing Real Number Lines

Here's another way to do what you want:

First move the y-axis to cross the x-axis at a large value that is outside the extent of the window. Then make a tiny function f(x)=0 and make its range right at the edge of the window and give it an arrow end. This does everything you want it to except that the arrow is a slightly different shape.

See the attached file for an example.

Hope this is helpful!


Post's attachments

Attachment icon Number Line.grf 1.75 kb, 498 downloads since 2011-09-07 

5 (edited by frame_of_mind 2011-09-12 03:08:36)

Re: Graphing Real Number Lines

Extending on the OP, can Graph be made to draw one-dimensional inequalities on a real number line?

There doesn't seem to be any solution to this problem. Neither Mathematica nor Maple has this feature. (It can be done, but not without some serious programming.)

If Graph could do this, then it would not only benefit all of us users, but also make it further stand out as one of the few easy-to-use graphing programs out there.

Re: Graphing Real Number Lines

Isn't a one dimentianal inequality just a horizontal line? Graph can do that. And you can use endpoints to indicate if the ends are included or not.

7 (edited by frame_of_mind 2011-09-12 08:00:19)

Re: Graphing Real Number Lines

The proposed solution is rigid and not much customization is possible. For example:

1. The tick mark over 0 is usually taller than the others on number line graphs.

2. Many algebra textbooks use brackets instead of dots for the endpoints. (See attachments.)

3. For compound inequalities, it's sometimes helpful to draw 2 inequalities on the same number line. (They are both drawn above the number line on top of each other so none of the lines overlap. See attachments.)

Being able to easily customize the picture's appearance is one of Graph's many strengths. Dedicated options for one-dimensional inequalities would be a welcome addition to a future version of Graph.

I use Graph all the time to make diagrams for the math classes I teach. It's an excellent program and I hope to see it become even better in the future!

Post's attachments

ineqslvh.gif, 663 b, 172 x 32
ineqslvh.gif 663 b, 498 downloads since 2011-09-12 

ineqslvi.gif, 684 b, 172 x 33
ineqslvi.gif 684 b, 514 downloads since 2011-09-12 

Screen-shot-2010-09-07-at-12.07.39-PM.png, 10.46 kb, 520 x 194
Screen-shot-2010-09-07-at-12.07.39-PM.png 10.46 kb, 508 downloads since 2011-09-12 

Screen-shot-2010-09-07-at-12.07.51-PM.png, 9.36 kb, 539 x 167
Screen-shot-2010-09-07-at-12.07.51-PM.png 9.36 kb, 502 downloads since 2011-09-12 

Re: Graphing Real Number Lines

1. Currently all tick marks are shown as the same.

2. Graph can show brackets but not square brackets as end points.

3. You can use functions with endpoints as inequalities.

I have attached a file that shows a way to do this. I might try to improve this in the future.

Post's attachments

Attachment icon 1D inequalities.grf 926 b, 478 downloads since 2011-09-12 

Re: Graphing Real Number Lines

Thank you very much. It would definitely be helpful to have options built into the UI for this purpose. It's possible to improvise some one-dimensional inequalities, but many users would not be able to figure it out. Maybe you could have a 1D-mode and a 2D-mode. Of course, 2D-mode would be the default.

By the way, is there a suggested donation amount for this program? smile

Re: Graphing Real Number Lines

frame_of_mind wrote:

By the way, is there a suggested donation amount for this program? smile

No, my suggestion is: The more the better wink
But any donation is appreciated.