Plotting complex numbers
06-09-2014, 11:14 PM
Post: #1
 Rich Junior Member Posts: 47 Joined: Jan 2014
Plotting complex numbers
Hi, is there a way to plot a function that includes a complex number on a 2-D plane? I have tried searching through the user guide v2 and this forum, but can't seem to find any documentation on it.

For example G(w)=100/(w*i)

I have attached a picture of a wolfram alpha plot below.

Thank you

06-10-2014, 03:13 AM
Post: #2
 Helge Gabert Senior Member Posts: 467 Joined: Dec 2013
RE: Plotting complex numbers
No, unfortunately, to my knowledge, only real functions can be plotted.

That would be a nice addition though, if the imaginary parts could be plotted as well for complex-valued functions . . .
06-10-2014, 04:07 AM (This post was last modified: 06-10-2014 11:45 AM by Rich.)
Post: #3
 Rich Junior Member Posts: 47 Joined: Jan 2014
RE: Plotting complex numbers
Thank you for the info.
06-10-2014, 11:39 AM (This post was last modified: 06-10-2014 11:40 AM by CR Haeger.)
Post: #4
 CR Haeger Member Posts: 275 Joined: Dec 2013
RE: Plotting complex numbers
I think you can use the RE() and IM() commands in the Function App like this:

to give this plot

I think your example only shows imaginary values. Other expressions of interest to plot using RE(), IM() might include:

100/(X*(1+i))
i^X
exp^(i*X)

Thanks for asking this! The Prime seems pretty useful for exploring real, imaginary functions this way.
06-10-2014, 11:44 AM
Post: #5
 Rich Junior Member Posts: 47 Joined: Jan 2014
RE: Plotting complex numbers
Awesome this is exactly what i needed! Thank you.
06-10-2014, 01:45 PM (This post was last modified: 06-10-2014 07:23 PM by Helge Gabert.)
Post: #6
 Helge Gabert Senior Member Posts: 467 Joined: Dec 2013
RE: Plotting complex numbers
(06-10-2014 11:39 AM)CR Haeger Wrote:  I think you can use the RE() and IM() commands in the Function App like this:

Thanks for pointing this out - - that works! I didn't think about IM() because it was somewhat unreliable (together with sqrt) in the previous firmware

but that appears to have been fixed in version 6030!
06-10-2014, 04:09 PM
Post: #7
 Wes Loewer Senior Member Posts: 415 Joined: Jan 2014
RE: Plotting complex numbers
(06-10-2014 11:39 AM)CR Haeger Wrote:  I think you can use the RE() and IM() commands in the Function App

That's very nice. And a good example of the importance of having color available.

-wes
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