1Let be a line in the Cartesian plane R2. Find a function f : ? R that is a coordinate function for.

1Let  be a line in the Cartesian plane R2. Find a function f :  _ R that is a coordinate function for in the square metric. (See Exercise 8 for definition of square metric.) 2. Let  be a line and let f :  _ R be a function such that PQ D |f P _ f Q| for every P,Q _ . Prove that f is a coordinate function for .