不定積分 $\small \displaystyle \int \dfrac{x^{n}}{x^{4}-1} \,dx$ の結果をまとめています。
$n \geqq 0$ の場合
（※$\operatorname{atan}$は正接（タンジェント）の逆関数）
$\small \displaystyle \int \dfrac{1}{x^{4}-1} \,dx$ $\small = \dfrac{\log{\left(x-1 \right)}}{4}-\dfrac{\log{\left(x + 1 \right)}}{4}-\dfrac{\operatorname{atan}{\left(x \right)}}{2} +C $
$\small \displaystyle \int \dfrac{x}{x^{4}-1} \,dx$ $\small = \dfrac{\log{\left(x^{2}-1 \right)}}{4}-\dfrac{\log{\left(x^{2} + 1 \right)}}{4} +C $
$\small \displaystyle \int \dfrac{x^{2}}{x^{4}-1} \,dx$ $\small = \dfrac{\log{\left(x-1 \right)}}{4}-\dfrac{\log{\left(x + 1 \right)}}{4} + \dfrac{\operatorname{atan}{\left(x \right)}}{2} +C $
$\small \displaystyle \int \dfrac{x^{3}}{x^{4}-1} \,dx$ $\small = \dfrac{\log{\left(x^{4}-1 \right)}}{4} +C $
$\small \displaystyle \int \dfrac{x^{4}}{x^{4}-1} \,dx$ $\small = x + \dfrac{\log{\left(x-1 \right)}}{4}-\dfrac{\log{\left(x + 1 \right)}}{4}-\dfrac{\operatorname{atan}{\left(x \right)}}{2} +C $
$\small \displaystyle \int \dfrac{x^{5}}{x^{4}-1} \,dx$ $\small = \dfrac{x^{2}}{2} + \dfrac{\log{\left(x^{2}-1 \right)}}{4}-\dfrac{\log{\left(x^{2} + 1 \right)}}{4} +C $
$\small \displaystyle \int \dfrac{x^{6}}{x^{4}-1} \,dx$ $\small = \dfrac{x^{3}}{3} + \dfrac{\log{\left(x-1 \right)}}{4}-\dfrac{\log{\left(x + 1 \right)}}{4} + \dfrac{\operatorname{atan}{\left(x \right)}}{2} +C $
$\small \displaystyle \int \dfrac{x^{7}}{x^{4}-1} \,dx$ $\small = \dfrac{x^{4}}{4} + \dfrac{\log{\left(x^{4}-1 \right)}}{4} +C $
$\small \displaystyle \int \dfrac{x^{8}}{x^{4}-1} \,dx$ $\small = \dfrac{x^{5}}{5} + x + \dfrac{\log{\left(x-1 \right)}}{4}-\dfrac{\log{\left(x + 1 \right)}}{4}-\dfrac{\operatorname{atan}{\left(x \right)}}{2} +C $
$\small \displaystyle \int \dfrac{x^{9}}{x^{4}-1} \,dx$ $\small = \dfrac{x^{6}}{6} + \dfrac{x^{2}}{2} + \dfrac{\log{\left(x^{2}-1 \right)}}{4}-\dfrac{\log{\left(x^{2} + 1 \right)}}{4} +C $
$\small \displaystyle \int \dfrac{x^{10}}{x^{4}-1} \,dx$ $\small = \dfrac{x^{7}}{7} + \dfrac{x^{3}}{3} + \dfrac{\log{\left(x-1 \right)}}{4}-\dfrac{\log{\left(x + 1 \right)}}{4} + \dfrac{\operatorname{atan}{\left(x \right)}}{2} +C $
$n < 0$ の場合
$\small \displaystyle \int \dfrac{1}{x \left(x^{4}-1\right)} \,dx$ $\small =-\log{\left(x \right)} + \dfrac{\log{\left(x^{4}-1 \right)}}{4} +C $
$\small \displaystyle \int \dfrac{1}{x^{2} \left(x^{4}-1\right)} \,dx$ $\small = \dfrac{\log{\left(x-1 \right)}}{4}-\dfrac{\log{\left(x + 1 \right)}}{4} + \dfrac{\operatorname{atan}{\left(x \right)}}{2} + \dfrac{1}{x} +C $
$\small \displaystyle \int \dfrac{1}{x^{3} \left(x^{4}-1\right)} \,dx$ $\small = \dfrac{\log{\left(x^{2}-1 \right)}}{4}-\dfrac{\log{\left(x^{2} + 1 \right)}}{4} + \dfrac{1}{2 x^{2}} +C $
$\small \displaystyle \int \dfrac{1}{x^{4} \left(x^{4}-1\right)} \,dx$ $\small = \dfrac{\log{\left(x-1 \right)}}{4}-\dfrac{\log{\left(x + 1 \right)}}{4}-\dfrac{\operatorname{atan}{\left(x \right)}}{2} + \dfrac{1}{3 x^{3}} +C $
$\small \displaystyle \int \dfrac{1}{x^{5} \left(x^{4}-1\right)} \,dx$ $\small =-\log{\left(x \right)} + \dfrac{\log{\left(x^{4}-1 \right)}}{4} + \dfrac{1}{4 x^{4}} +C $
$\small \displaystyle \int \dfrac{1}{x^{6} \left(x^{4}-1\right)} \,dx$ $\small = \dfrac{\log{\left(x-1 \right)}}{4}-\dfrac{\log{\left(x + 1 \right)}}{4} + \dfrac{\operatorname{atan}{\left(x \right)}}{2} + \dfrac{5 x^{4} + 1}{5 x^{5}} +C $
$\small \displaystyle \int \dfrac{1}{x^{7} \left(x^{4}-1\right)} \,dx$ $\small = \dfrac{\log{\left(x^{2}-1 \right)}}{4}-\dfrac{\log{\left(x^{2} + 1 \right)}}{4} + \dfrac{3 x^{4} + 1}{6 x^{6}} +C $
$\small \displaystyle \int \dfrac{1}{x^{8} \left(x^{4}-1\right)} \,dx$ $\small = \dfrac{\log{\left(x-1 \right)}}{4}-\dfrac{\log{\left(x + 1 \right)}}{4}-\dfrac{\operatorname{atan}{\left(x \right)}}{2} + \dfrac{7 x^{4} + 3}{21 x^{7}} +C $
$\small \displaystyle \int \dfrac{1}{x^{9} \left(x^{4}-1\right)} \,dx$ $\small =-\log{\left(x \right)} + \dfrac{\log{\left(x^{4}-1 \right)}}{4} + \dfrac{2 x^{4} + 1}{8 x^{8}} +C $
$\small \displaystyle \int \dfrac{1}{x^{10} \left(x^{4}-1\right)} \,dx$ $\small = \dfrac{\log{\left(x-1 \right)}}{4}-\dfrac{\log{\left(x + 1 \right)}}{4} + \dfrac{\operatorname{atan}{\left(x \right)}}{2} + \dfrac{45 x^{8} + 9 x^{4} + 5}{45 x^{9}} +C $