My answer would be correct if I didn't have that extra x variable. Why do I have it and how do I get rid of it?

Any input would be greatly appreciated!

Thanks in advance!

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- Feb 23rd 2010, 08:59 AMs3aProve a simple reduction formula (I get it almost right)
My answer would be correct if I didn't have that extra x variable. Why do I have it and how do I get rid of it?

Any input would be greatly appreciated!

Thanks in advance! - Feb 23rd 2010, 09:05 AMTed
Your $\displaystyle du$ is wrong. It should be : $\displaystyle du = n \left( ln(x) \right) ^{n-1} {\color{red} \frac{1}{x}} dx$.

Recall that:

If $\displaystyle n \in R$ and $\displaystyle y=\left( f(x) \right)^n$ , then:

$\displaystyle y' = n \left( f(x) \right)^{n-1} {\color{red} f'(x)}$.