I (now) know that I can check the following by differentiating my answer, but I don't trust my differentiation.(adsbygoogle = window.adsbygoogle || []).push({});

Problem is as follows:

[tex]\int\tan^4{3x}\sec^2{3x}dx[/tex]

I assigned u=tan(3x), du=3sec^2(3x) and got that integral in terms of u:

[tex]\frac{1}{3}\int u^4du[/tex]

[tex] =\frac{1}{3}\times\frac{u^5}{5}+C[/tex]

[tex] =\frac{\tan^5(3x)}{15}+C[/tex]

I think that differentiates into what's in the original integral, but as I haven't differentiated anything that looks like that for a while now, I'd appreciate some feedback.

Thanks!

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# Homework Help: More integration by subsitution

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