Remove updated by ... comment, added categories

and updated others for consistency.

Author: pstaabp

tutorial/sample-problems/Parametric/PolarGraph.pg

@@ -56,7 +56,7 @@ BEGIN_PGML
 Find the area enclosed by one petal of the rose curve
 [`r = f(\theta) = \cos(5\theta)`].
 
->>[!a rose curve!]{$graph}{300}<<  
+>>[!a rose curve!]{$graph}{300}<<
 >>Graph of [`r = \cos(5\theta)`]<<
 
 Area = [_____]{'pi / 20'}