f R SolutionConsidering f l R is a coordinate function for

Solution

Considering f: l --> R is a coordinate function for l.

Let consider two points P and Q on l,

According to definition of coordinate function -

PQ = | f(P) - f(Q) |

Since => |a| = |-a|

PQ = | f(Q) - f(P) |

PQ = | -f(P) - (-f(Q)) |

So you can say -f is also a coordinate function for l.