Primitive of Reciprocal of x by a squared minus x squared


 * $\ds \int \frac {\d x} {x \paren {a^2 - x^2} } = \frac 1 {2 a^2} \map \ln {\frac {x^2} {a^2 - x^2} } + C$

for $x^2 < a^2$.

Also see

 * Primitive of $\dfrac 1 {x \paren {x^2 - a^2} }$