Problem with Plot of Solution for NDSolve [closed]

I'm trying to plot the solution of an equation using NDSolve. For some reason nothing shows up in the plot. I checked the output of the interpolating function and it doesn't look like there is anything wrong with the data - though I could be wrong - so I'm just trying to figure out what is going on.

     q2 = NDSolve[{u'[ϕ] == -Sqrt[3 - 2 u[ϕ] ArcSech[1/u[ϕ]]/Sqrt[u[ϕ]^2 - 1]],
u[1.494706195984861] == 3.208921901232091},
u, {ϕ, 1.494706195984861, 20}]


Then when I use PolarPlot to plot the function, nothing appears:

s2 = PolarPlot[Evaluate[1/u[ϕ] /. q2], {ϕ, 1.494706195984861, 14.708465676522565},
PlotRange -> All, PlotStyle -> Thick]


Thanks in advance for any help.

closed as off-topic by Sjoerd C. de Vries, m_goldberg, bobthechemist, C. E., rm -rf♦Jan 25 '14 at 14:48

This question appears to be off-topic. The users who voted to close gave this specific reason:

• "This question arises due to a simple mistake such as a trivial syntax error, incorrect capitalization, spelling mistake, or other typographical error and is unlikely to help any future visitors, or else it is easily found in the documentation." – Sjoerd C. de Vries, m_goldberg, bobthechemist, C. E., rm -rf
If this question can be reworded to fit the rules in the help center, please edit the question.

• it is complex. Try s2 = PolarPlot[Evaluate[Re[1/u[\[Phi]] /. q2]], {\[Phi], 1.494706195984861, 14.708465676522565}, PlotRange -> All, PlotStyle -> Thick] !Mathematica graphics – Nasser Jan 24 '14 at 17:42
• And the imaginary part isn't negligible ... – Dr. belisarius Jan 24 '14 at 17:47
• @Nasser, Thank you! – Nicole Jan 26 '14 at 19:15
• @belisarius, Thanks! – Nicole Jan 26 '14 at 19:16

As pointed out in the comments, your result is complex. You could split real and imaginary part and plot them together:

PolarPlot[Evaluate[{Re[#], Im[#]} & @@ (1/u[\[Phi]] /. q2)],
{\[Phi], 1.494706195984861, 14.708465676522565},
PlotRange -> All, PlotStyle -> Thick]


• Perfect. Thank you! – Nicole Jan 26 '14 at 19:14