This is LaTeX code:

[latex]
\sum\limits_{i \ge 2} {x^{i - 1} } = \frac{1}{{1 - x}} - 1 \Rightarrow \sum\limits_{i \ge 2} {\frac{{x^i }}{i}} = - \ln \left( {1 - x} \right) - x \Rightarrow
[/latex]