Suppose that $f$ and $g$ are two analytic functions on the set $\phi$ of all complex numbers with $f(\frac{1}{n})=g(\frac{1}{n})$ for $n=1,2,3,\ldots$ Then show that $f(z)=g(z)$ for each $z$ in $\phi$.
I am not able to even start proving it. Can some one please help me?