## Mathematica

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### Mathematica

I am trying to graph the equation 3Cos[t]+iSin[t] in Mathematica. I have no problem with the 3Cos[t]+Sin[t], but I cannot seem to make Mathematica recognize the i (nor I when I capitalize it). Is there some trick to getting it to plot this correctly? I am using the following:
r[t_] = 3 Cos[t] + Sin[t];
PolarPlot[r[t], {t, -Pi/2, Pi/2}]

Thanks!
phoebe
Newcomer

Posts: 8
Joined: Wed Nov 02, 2011 8:09 pm

### Re: Mathematica

i is I in Mathematica, but you don't need to use it at all if you're plotting parametrically:
Code: Select all
`ParametricPlot[{3 Cos[t], Sin[t]}, {t, -Pi/2, Pi/2}]`

I'm not sure if this is what you're trying to do, though. You write PolarPlot, but of course the radius can't be nonreal so I'm not sure how to adapt that.
Pari/GP: this is the program I probably mentioned in my post. Windows users can get it at http://pari.math.u-bordeaux.fr/pub/pari ... -2-6-1.exe

CRGreathouse
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Posts: 12067
Joined: Sat Nov 25, 2006 9:52 am
Location: UTC -5

### Re: Mathematica

OK, it looks like I need to use parametricplot, but I need for the functions to be added together. I'll try that; thanks.
phoebe
Newcomer

Posts: 8
Joined: Wed Nov 02, 2011 8:09 pm

### Re: Mathematica

phoebe wrote:I need for the functions to be added together.

The argument, in your case, is {RealPart, ImaginaryPart}; if you like you can write
Code: Select all
`f[x_] := (*some complex function here*)ParametricPlot[{Re[f[t]], Im[f[t]]}, {t, -Pi/2, Pi/2}]`
Pari/GP: this is the program I probably mentioned in my post. Windows users can get it at http://pari.math.u-bordeaux.fr/pub/pari ... -2-6-1.exe

CRGreathouse
Global Moderator

Posts: 12067
Joined: Sat Nov 25, 2006 9:52 am
Location: UTC -5