Let f(x) = x^9+x^2+4. Prove: The equation f(x)=0 has at least one real solution.
The Attempt at a Solution
I know that the solution lies between -2 and -1. I also know that f(-2) = -504 and f(-1) = 4. I need to know how to use the IVT to prove that there is one real solution; not sure how to do that.