Revert theta use for now.

Author: rocky

mathics/builtin/drawing/plot.py

@@ -2198,14 +2198,14 @@ def eval_f(self, f, x_value):
 class PolarPlot(_Plot):
     u"""
     <dl>
-      <dt>'PolarPlot[$r$, {$\u03B8$, $\u03B8_min$, $\u03B8_max$}]'
-      <dd>creates a polar plot of curve with radious $r$ as a function of angle $\u03B8$ ranging from $\u03B8_min$ to $\u03B8_max$.
+      <dt>'PolarPlot[$r$, {$t$, $t_min$, $t_max$}]'
+      <dd>creates a polar plot of curve with radious $r$ as a function of angle $t$ ranging from $t_min$ to $t_max$.
     </dl>
 
     >> PolarPlot[Cos[5\\[Theta]], {\\[Theta], 0, Pi}]
      = -Graphics-
 
-    >> PolarPlot[{1, 1 + Sin[20 \u03B8] / 5}, {\u03B8, 0, 2 Pi}]
+    >> PolarPlot[{1, 1 + Sin[20 t] / 5}, {t, 0, 2 Pi}]
      = -Graphics-
 
     >> PolarPlot[Sqrt[t], {t, 0, 16 Pi}]

mathics/doc/tex/mathics.tex

@@ -61,8 +61,6 @@
     {ü}{{\"u}}1
     {ä}{{\"a}}1
     {ö}{{\"o}}1
-    {θ}{{$\theta$}}
-    {γ}{{$\gamma$}}
     {~}{{\textasciitilde}}1
     {⧦}{{===}}1
     {}{{=>}}1