Primitive of Reciprocal of a squared minus x squared squared

Theorem

 * $\ds \int \frac {\d x} {\paren {a^2 - x^2}^2} = \frac x {2 a^2 \paren {a^2 - x^2} } + \frac 1 {4 a^3} \map \ln {\frac {a + x} {a - x} } + C$

for $x^2 < a^2$.

Also see

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