(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

[tex]\int x^2*cosx dx[/tex]

2. Relevant equations

3. The attempt at a solution

Okay, so I started by making...

u=x^2

du=2x

dv=cos(x)

v=-sin(x)

Then I made the rudimentary equation:

[tex]\int x^2 * cos(x) dx = -x^2*sin(x) + \int 2x * sin(x) dx[/tex]

Then I took the last integration problem (the one all the way on the right) and did integration by parts on that one again, to make:

u=2x

du=2

dv=sin(x)

v=-cos(x)

to make...

[tex]\int x^2 * cos(x) dx = -x^2 * sin(x) + 2x * sin(x) + \int 2 * cos(x) dx[/tex]

I evaluated the last integration problem to be -2*sin(x), and got a final answer of sin(x)(-x^2+2x-2) (after factoring). Of course, my calculator says this is wrong, so where'd I mess up?

Thanks. (I'm getting better with Latex, btw)

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# Homework Help: Integration (by parts) check my work

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