# Math Help - Limit of sum-fonction

1. ## Limit of sum-fonction

For all naturel number n .
the function :
Calculate :

2. Isn't clear that $f_n (x) = \sum\limits_{k = 0}^n {\frac{{x^2 }}{{\left( {1 + x^2 } \right)^k }}} ?$

Also that $\left( {\forall x} \right)\left[ {\frac{1}{{\left( {1 + x^2 } \right)}} \leqslant 1} \right]$.

3. hi
$\frac{x^{2}}{(1+x^{2})^{n}}$ $\to 0$
while $n \to +\infty$
i might be wrong,i'm just trying to help