Forum for the GRE subject test in mathematics.
- Posts: 1
- Joined: Fri Oct 03, 2014 10:24 pm
Suppose that f(x+1)=f(x) for all real x. If f is a polynomial and f(5) = 11, the f(15/2) is:
e)not uniquely determined by the information given
I thought answer e) but actually it's c), I don't figure out why?
- Posts: 4
- Joined: Sun Oct 19, 2014 12:09 am
The key is to realize that f is a polynomial and use the fact that f(5) = 11 with f(x) = f(x+1) for all real x to deduce it must be constant. Hence, you can obtain f(7.5).