Expression 1: distance left parenthesis, left parenthesis, "x" , "y" , right parenthesis , token 2 , right parenthesis plus distance left parenthesis, left parenthesis, "x" , "y" , right parenthesis , token 3 , right parenthesis plus distance left parenthesis, left parenthesis, "x" , "y" , right parenthesis , token 4 , right parenthesis equals 20distancex,y,A+distancex,y,C+distancex,y,B=20
1
An ellipse is the set of points P such that sum of the distances to two points, A and B, is constant. Suppose we take this a step further: What is the set of points P such that the sum of the distances to three points, A, B, and C, is constant?