Primitive of Power of x over Power of Power of x minus Power of a
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Theorem
- $\ds \int \frac {x^m \rd x} {\paren {x^n - a^n}^r} = a^n \int \frac {x^{m - n} \rd x} {\paren {x^n - a^n}^r} + \int \frac {x^{m - n} \rd x} {\paren {x^n - a^n}^{r - 1} }$
Proof
\(\ds \int \frac {x^m \rd x} {\paren {x^n - a^n}^r}\) | \(=\) | \(\ds \int \frac {x^{m - n} x^n \rd x} {\paren {x^n + a^n}^r}\) | ||||||||||||
\(\ds \) | \(=\) | \(\ds \int \frac {x^{m - n} \paren {x^n - a^n + a^n} \rd x} {\paren {x^n - a^n}^r}\) | ||||||||||||
\(\ds \) | \(=\) | \(\ds \int \frac {x^{m - n} \paren {x^n - a^n} \rd x} {\paren {x^n - a^n}^r} + a^n \int \frac {x^{m - n} \rd x} {\paren {x^n - a^n}^r}\) | Linear Combination of Primitives | |||||||||||
\(\ds \) | \(=\) | \(\ds a^n \int \frac {x^{m - n} \rd x} {\paren {x^n - a^n}^r} + \int \frac {x^{m - n} \rd x} {\paren {x^n - a^n}^{r - 1} }\) | simplification |
$\blacksquare$
Sources
- 1968: Murray R. Spiegel: Mathematical Handbook of Formulas and Tables ... (previous) ... (next): $\S 14$: Integrals involving $x^n \pm a^n$: $14.332$