Do I use integration by substitution?? this is a really tricky question for me

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- Dec 13th 2012, 11:04 PMasilvester635Calculus integration (hard)
Do I use integration by substitution?? this is a really tricky question for me

- Dec 13th 2012, 11:35 PMMarkFLRe: Calculus integration (hard)
Yes, try the substitution:

$\displaystyle u=1-x\,\therefore\,du=-dx$

Then use:

$\displaystyle \sec(u)\tan(u)=\frac{d}{du}(sec(u))$ - Dec 14th 2012, 09:06 AMasilvester635Re: Calculus integration (hard)
LOL so the final answer is sec(1-x)... wow it's that easy...

- Dec 14th 2012, 11:07 PMMarkFLRe: Calculus integration (hard)
Not quite that easy...you need to correctly substitute for the differential to get:

$\displaystyle -\int\,d(\sec(u))=-\sec(u)+C=-\sec(1-x)+C$