This is what I have so far:(adsbygoogle = window.adsbygoogle || []).push({});

[tex]\int (\frac{x^2}{\sqrt{4 + x^2}}) dx [/tex]

[tex]x = 2 tan u[/tex]

[tex]dx = (2 sec^2u) du[/tex]

[tex]x^2 = 4 tan^2 u[/tex]

[tex]\sqrt{4 + x^2} = \sqrt{4 + 4 tan^2 u}[/tex]

[tex]\sqrt{4 + x^2} = \sqrt{4 (1 + tan^2 u}[/tex]

[tex]\sqrt{4 + x^2} = \sqrt{4 sec^2 u}[/tex]

[tex]\sqrt{4 + x^2} = 2 sec u[/tex]

Then I have:

[tex]\int (\frac{x^2}{\sqrt{4 + x^2}}) dx = \int \frac{4 tan^2 u}{2 sec u} 2 sec^2 u du[/tex]

[tex]\int (\frac{x^2}{\sqrt{4 + x^2}}) dx = \int (4 tan^2 u)(sec u) du[/tex]

I keep getting stuck on this part, any ideas?

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# One last integration problem

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