Graphics, Figures & Tables ⇒ PSTricks | Radian Units for Polar Plots

[coachbennett1981]

I found a great example of polar coordinates that are in degree mode. Is there a way I can change the degrees to radian measure? Here is the code.

Code: Select all

\begin{pspicture}(-3.5,-3.5)(3.5,3.5)
  \psaxes[axesstyle=polar,subticklinestyle=dashed,subticks=2,labelFontSize=\scriptstyle](3,3)
  \psplot[polarplot,algebraic,linecolor=red,linewidth=2pt,plotpoints=2000]{0}{TwoPi}{6*sin(x)*cos(x)}
\end{pspicture}

[retrogrouch]

You can calculate inside the parameters list so I'm guessing you could use something like 360*radians/(2*pi) in place of x. The manual goes into a lot of detail about calculations.


Laurie

[localghost]

What makes you think that the function is in degree mode? I think that a domain from 0 to 2*Pi already represents radians.


Best regards and welcome to the board
Thorsten

[CrazyHorse]

With algebraic=true the angles are always in radian!


Herbert

[coachbennett1981]

Thanks for the replies from everyone. When you run the diagram each angle measure is in degree, I am wondering if it can be made to show the radians instead of the degree. I see the code 0 to 2*pi. I should have been more clear, I want to show the polar coordinate plane in radians, not degrees, I was not talking about the function given.


Thank you
Nick

[CrazyHorse]

A quick hack ...

Code: Select all

\documentclass{article}
\usepackage{pstricks-add}

\def\psvlabel#1{%
  \ifnum#1=30 $\frac{\pi}{6}$\else
  \ifnum#1=180 $\pi$\else
  \ifnum#1=360 $2\pi$\else
  \pstFPDiv\Val{#1}{30}$\frac{\Val\pi}{6}$%
  \fi\fi\fi}

\begin{document}
  \begin{pspicture}(-3.5,-3.5)(3.5,3.5)
    \psaxes[axesstyle=polar,subticklinestyle=dashed,subticks=2,labelFontSize=\scriptstyle](3,3)
    \psplot[polarplot,algebraic,linecolor=red,linewidth=2pt,plotpoints=2000]{0}{TwoPi}{6*sin(x)*cos(x)}
  \end{pspicture}
\end{document}

Herbert

[nftaussig]

You can modify Herbert's code to get the radian measures in reduced form as follows.

Code: Select all

\documentclass{article}
\usepackage{pstricks-add}
\def\psvlabel#1{%
  \ifnum#1=30 $\frac{\pi}{6}$\else
  \ifnum#1=60 $\frac{\pi}{3}$\else
  \ifnum#1=90 $\frac{\pi}{2}$\else 
  \ifnum#1=120 $\frac{2\pi}{3}$\else 
  \ifnum#1=180 $\pi$\else
  \ifnum#1=240 $\frac{4\pi}{3}$\else
  \ifnum#1=270 $\frac{3\pi}{2}$\else 
  \ifnum#1=300 $\frac{5\pi}{3}$\else  
  \ifnum#1=360 $2\pi$\else
  \pstFPDiv\Val{#1}{30}$\frac{\Val\pi}{6}$%
  \fi\fi\fi\fi\fi\fi\fi\fi\fi}    

\begin{figure}
\begin{center}
\begin{document}
\begin{pspicture}(-3.5,-3.5)(3.5,3.5)
  \psaxes[axesstyle=polar,subticklinestyle=dashed,
  subticks=2,labelFontSize=\scriptstyle](3,3)
  \psplot[polarplot,algebraic,linecolor=red,
  linewidth=2pt,plotpoints=2000]{0}{TwoPi}{6*sin(x)*cos(x)}
\end{pspicture}
\end{center}
\caption{$r(\theta) = 6\sin\theta\cos\theta$.}
\end{figure}

\end{document}

[nftaussig]

After reviewing my previous post, I realized that I made an error. The corrected version follows.

Code: Select all

\documentclass{article}
\usepackage{pstricks-add}
\def\psvlabel#1{%
  \ifnum#1=30 $\frac{\pi}{6}$\else
  \ifnum#1=60 $\frac{\pi}{3}$\else
  \ifnum#1=90 $\frac{\pi}{2}$\else
  \ifnum#1=120 $\frac{2\pi}{3}$\else
  \ifnum#1=180 $\pi$\else
  \ifnum#1=240 $\frac{4\pi}{3}$\else
  \ifnum#1=270 $\frac{3\pi}{2}$\else
  \ifnum#1=300 $\frac{5\pi}{3}$\else  
  \ifnum#1=360 $2\pi$\else
  \pstFPDiv\Val{#1}{30}$\frac{\Val\pi}{6}$%
  \fi\fi\fi\fi\fi\fi\fi\fi\fi}    

\begin{document}

\begin{figure}[h]
\begin{center}
\begin{pspicture}(-3.5,-3.5)(3.5,3.5)
  \psaxes[axesstyle=polar,subticklinestyle=dashed,
  subticks=2,labelFontSize=\scriptstyle](3,3)
  \psplot[polarplot,algebraic,linecolor=red,
  linewidth=2pt,plotpoints=2000]{0}{TwoPi}{6*sin(x)*cos(x)}
\end{pspicture}
\end{center}
\end{figure}

\end{document}