Question Number 26722 by prakash jain last updated on 28/Dec/17
$$\underset{{x}\rightarrow−\mathrm{1}^{+} } {\mathrm{lim}}\left(\mathrm{1}+{x}+{x}^{\mathrm{2}} +{x}^{\mathrm{3}} +…\mathrm{up}\:\mathrm{to}\:\infty\right)=? \\ $$$$\underset{{x}\rightarrow−\mathrm{1}^{−} } {\mathrm{lim}}\left(\mathrm{1}+{x}+{x}^{\mathrm{2}} +{x}^{\mathrm{3}} +…\mathrm{up}\:\mathrm{to}\:\infty\right)=? \\ $$