10.9-bo'lim: Mutlaq yaqinlashuv

Quyidagi ketma-ketliklarning har biri uchun ularning mutlaq yaqinlashishi, shartli yaqinlashishi yoki divergentligini aniqlang.

1. \( \displaystyle \sum\limits_{n = 2}^\infty {\frac{{{{\left( { - 1} \right)}^{n + 1}}}}{{{n^3} + 1}}} \) Yechim
2. \( \displaystyle \sum\limits_{n = 1}^\infty {\frac{{{{\left( { - 1} \right)}^{n - 3}}}}{{\sqrt n }}} \) Yechim
3. \( \displaystyle \sum\limits_{n = 3}^\infty {\frac{{{{\left( { - 1} \right)}^{n + 1}}\left( {n + 1} \right)}}{{{n^3} + 1}}} \) Yechim