Question

Getting slightly wrong answer trying to integrate y*sqrt(y-2) by parts

Answer 1

\[\int y\sqrt{y-2}dy\]?

Answer 2

Yes. WolframAlpha gives me: http://www.wolframalpha.com/input/?i=integrate+y*sqrt%7By-2%7D which is not my answer. Can't figure out what I'm doing wrong.

Answer 3

first off i would not integrate by parts
unless you are told you have to

Answer 4

Good point.

Answer 5

There's a nice simple u-substitution for this one :)
Not seeing it?

Answer 6

It a neat little trick that maybe you haven't considered.\[\large\rm \color{orange}{u=y-2}\qquad\to\qquad \color{red}{u+2=y}\]\[\large\rm \color{blue}{du=dy}\]
\[\large\rm \int\limits \color{red}{y}\sqrt{\color{orange}{y-2}}~\color{blue}{dy}=?\]Do you see how that will help here? :o

Answer 7

Thanks so much for the help, but I already solved it with u-substitution and am just utterly stumped as to why I can't get the right answer with integration by parts. Should I just give up on that? :)

Answer 8

Oh :o checking

Answer 9

ok i think i see a boo boo...

Answer 10

Missing a 2 here :o