Integral x^2 cosx

[hajfajv]

I know my work is wrong but I cannot find where I make mistakes

 

[topsquark]

I know my work is wrong but I cannot find where I make mistakes

You didn't distribute the 2 from the first partial integration.

-Dan

 

[Dr.Peterson]

I know my work is wrong but I cannot find where I make mistakes

Here are two errors:

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In both cases, you changed a multiplication into an addition or subtraction, by omitting necessary parentheses.

Fix the first error, and continue from there.