# Which methods to use to find the integrals.

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• March 16th 2013, 11:17 AM
jennybee
Which methods to use to find the integrals.
I'm trying to find the indefinite integrals for the two equations below. What methods do I use to solve?

Attachment 27559

Attachment 27560 (-1 < x < 1)

Thanks
• March 16th 2013, 11:23 AM
Kanwar245
Re: Which methods to use to find the integrals.
The first one can be solved by integration by parts, let $u = arctan x, dv = 2x^3 + x$
Second one can be done easily by a substitution of $u = 1 - x^2$
• March 16th 2013, 11:23 AM
TheEmptySet
Re: Which methods to use to find the integrals.
Quote:

Originally Posted by jennybee
I'm trying to find the indefinite integrals for the two equations below. What methods do I use to solve?

Attachment 27559

Attachment 27560 (-1 < x < 1)

Thanks

For the first one use integration by parts

$u=\tan^{-1}(x) \quad dv=2x^3+x$

For the 2nd one use a u du substitution

$u=1-x^2$
• March 16th 2013, 11:26 AM
jennybee
Re: Which methods to use to find the integrals.
Thanks to both of you. Loving the Sephiroth avatar :)