1. The problem statement, all variables and given/known data Basically, I had a test yesterday and one of the questions was: "an odd function f(x) has a period τ=7. What is the value of f(75)-f(-30)" 2. Relevant equations n/a 3. The attempt at a solution I used periodicity to reduce = f(75-70) + f(30-28) = f(5) + f(2) What else could I have done?