1. The problem statement, all variables and given/known data A function from the real numbers to the real numbers is one to one on an interval I if it is strictly increasing on that interval. Any help please!!! 2. Relevant equations 3. The attempt at a solution I am not quite sure how to prove it, I know that the use of strictly increasing is important as far as if x1 < x2, then f(x1) < f(x2). A hint I was told to use is contradiction.