Question

Неопределенный интеграл

$\int\limits {\frac{1}{9x^{2} - 1} } \, dx$

Answer 1

$\int\limits {\dfrac{1}{9x^2-1}} \, dx = \int\limits {\dfrac{1}{(3x-1)(3x+1)}} \, dx =\dfrac{1}{6} (\int\limits {\dfrac{1}{3x-1}} \, d(3x-1) - \int\limits {\dfrac{1}{3x+1}} \, d(3x+1))=\dfrac{1}{6} ln \left| \dfrac{3x-1}{3x+1} \right|+C$