1. The problem statement, all variables and given/known data A function from R-->R is differentiable and follows f( (x+y)/3 ) =( 2 + f(x) + f(y) ) / 3 Derivative of f(x) at x=2 is 2 Find the range of f ( |x| ) 2. Relevant equations 3. The attempt at a solution Well the questions asks me the range of f( |x| ). But i don't even know f(x). I did find the value of f(0) which is 2. And i don't know what to do afterwards. I have no idea why the value of derivative is given.