I am having some trouble with:

integral of $\displaystyle xcos(x^3)$

any ideas?

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- May 4th 2010, 03:52 PMCalculusCrazedEvaluate the indefinite integral as an infinite series
I am having some trouble with:

integral of $\displaystyle xcos(x^3)$

any ideas? - May 4th 2010, 03:57 PMskeeter
$\displaystyle \cos{x} = 1 - \frac{x^2}{2!} + \frac{x^4}{4!} - \frac{x^6}{6!} + ...$

$\displaystyle \cos(x^3) = 1 - \frac{x^6}{2!} + \frac{x^{12}}{4!} - \frac{x^{18}}{6!} + ...$

$\displaystyle x\cos(x^3) = x - \frac{x^7}{2!} + \frac{x^{13}}{4!} - \frac{x^{19}}{6!} + ...$

integrate it, term for term ...