Originally Posted by

**coobe** this is part of an integration, thats why i posted it here.

the needed substitution here is $\displaystyle u=sin(x)$

i end up with this sometime, which is correct:

$\displaystyle 2\sqrt{sin(x)}-\frac{2*\sqrt{sin(x^5)}}{5}+C$ $\displaystyle {\color{red} 2\sqrt{sin(x)}-\frac{2*\sqrt{(sin(x))^5}}{5}+CMr F says: You mean }$.

now my book says the result should be:

$\displaystyle \frac{2}{5}\sqrt{sin(x)}[4+cos^2(x)]+C$

and wofram alpha says it should be:

$\displaystyle \frac{1}{5}\sqrt{sin(x)}[cos(2x)+9]+C$

to be honest... i tried and i tried, i dont get it how i will get any of those 2 solutions. would be so nice if someone could explain it me reeeeal slow :)

thx in advance