Primitives involving Power of x squared plus a squared

Theorem

This page gathers together the primitives of some expressions involving $\left({x^2 + a^2}\right)^n$.

Primitive of Reciprocal of $\left({x^2 + a^2}\right)^n$

$\ds \int \frac {\d x} {\paren {x^2 + a^2}^n} = \frac x {2 \paren {n - 1} a^2 \paren {x^2 + a^2}^{n - 1} } + \frac {2 n - 3} {\paren {2 n - 2} a^2} \int \frac {\d x} {\paren {x^2 + a^2}^{n - 1} }$

Primitive $x$ over $\left({x^2 + a^2}\right)^n$

$\ds \int \frac {x \rd x} {\paren {x^2 + a^2}^n} = \frac {-1} {2 \paren {n - 1} \paren {x^2 + a^2}^{n - 1} }$

Primitive of Reciprocal of $x \left({x^2 + a^2}\right)^n$

$\ds \int \frac {\d x} {x \paren {x^2 + a^2}^n} = \frac 1 {2 \paren {n - 1} a^2 \paren {x^2 + a^2}^{n - 1} } + \frac 1 {a^2} \int \frac {\d x} {x \paren {x^2 + a^2}^{n - 1} }$

Primitive of $x^m$ over $\left({x^2 + a^2}\right)^2$

$\ds \int \frac {x^m \rd x} {\paren {x^2 + a^2}^n} = \int \frac {x^{m - 2} \rd x} {\paren {x^2 + a^2}^{n - 1} } - a^2 \int \frac {x^{m - 2} \rd x} {\paren {x^2 + a^2}^n}$

Primitive of Reciprocal of $x^m \left({x^2 + a^2}\right)^n$

$\ds \int \frac {\d x} {x^m \paren {x^2 + a^2}^n} = \frac 1 {a^2} \int \frac {\d x} {x^m \paren {x^2 + a^2}^{n - 1} } - \frac 1 {a^2} \int \frac {\d x} {x^{m - 2} \paren {x^2 + a^2}^n}$

Also see

• Primitives involving $x^2 + a^2$
• Primitives involving $\left({x^2 + a^2}\right)^2$