$$\lim\limits_{\mathrm{n} \rightarrow \infty} \tan \left\{\sum\limits_{\mathrm{r}=1}^{\mathrm{n}} \tan ^{-1}\left(\frac{1}{1+\mathrm{r}+\mathrm{r}^{2}}\right)\right\}$$ बराबर है ____________ |