Programming for Mathematics
Assignment, 18 August 2014

1. Extend the definition of the class Point (see below) that uses an
   (r,theta) internal representation of a point to include the
   following functions.

   distance(p)

     Returns the Euclidean distance between the given point and
     another point p.

   translate(deltax,deltay)

     Shifts the given point from (x,y) to (x+deltax,y+deltay)

2. Should it be considered acceptable for these functions to
   directly access and make use of the internal state variables r
   and theta --- in particular, for distance(p), which needs to
   extract the coordinates of p?  

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from math import *

class Point:

    def __init__(self,a,b):
        self.r = sqrt(a*a + b*b)
        self.theta = atan(float(b)/a)

    def setpoint(self,a,b):
        self.r = sqrt(a*a + b*b)
        self.theta = atan(float(b)/a)

    def getpoint(self):
        x = self.r*(cos(self.theta))
        y = self.r*(sin(self.theta))
        return(x,y)
        
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