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## Homework Statement

[1] integral of 2x / (4+x^2)

[2] [tex]\int \frac{3}{\abs{x}\sqrt{x^{6}-1}}[/tex]

(the x above is absolute |x|, can't find the latex code...

## Homework Equations

## The Attempt at a Solution

[1] can be done easily using natural log method.

ln|4+x^2| +c

The reason I asked this was because this question belong to "The Caclulus of The Inverse Trig Functions", where it introduced how to take d/dx and integral of arcsin, arccos, arctan, etc.

I was wondering if [1] can be done by arctan... arctan = integral of 1/1+x^2

[2] It was very similar to integral of sec, integral of 1/ (|x| sqrt(x^2-1))

I tried to factor out those x and reduce it to x^3, but still no luck, because of |x|

Any help is appreciated.

Thanks