title: Plot mathematical relations like a circle with equation x^2+y^2=c^2
body: <p>I want to use to "mpandroidchart" library to plot mathematical functions and relations. 
  Can it be used to plot a circle and other relations ?
  I am using Acharengine to plot functions but , Achartengine doesn't have support to plot relations (one to many). So I want to ask if it is possible with this library. </p>