let be 2 analytic function so in the real line for every real number 'x' then
$$ f(x)=g(x) $$
then can we assure that for every 'z' complex number can we also have
$$ f(z)=g(z) $$
so if 2 functions are equal for are the real numbers then they are also equal for every complex number, if they ara analytic whitout poles