integration

GemmaJ1988 · 2008-10-29 08:40:42

hi i'm not sure wether im integrating the following function properly

i know this function integrated with respect to x in lnx
if i integrate it with respect to y do i get lnxy
please help, will be very much appreciated!!

mathsyperson · 2008-10-29 09:15:12

If x and y are independent, then you can treat 1/x as a constant and you'll end up with y/x + c.

If x = f(y), then write x in terms of y and try integrating it then.

GemmaJ1988 · 2008-10-30 02:59:26

Thank you that was actually very simple!
another integration problem which has left me unsure is the following

i know the following is true

can i just aply this to get:

does anyone know if this is correct? please help

Daniel123 · 2008-10-30 03:05:01

No, that is incorrect.

Use integration by parts, where

and .

Last edited by Daniel123 (2008-10-30 03:05:28)

GemmaJ1988 · 2008-10-30 03:12:38

im not sure how to integrate

though. can anyone show me how??

can i rearrange this to be

then integrate

i feel this might complicate things

Last edited by GemmaJ1988 (2008-10-30 03:16:05)

Daniel123 · 2008-10-30 03:35:09

You don't have to directly integrate it.

Now use integration by parts, where you integrate

and differentiate .

GemmaJ1988 · 2008-10-30 04:44:14

ok so i've done this and i've got

does this seem correct?

Daniel123 · 2008-10-30 04:49:48

Yes, that's correct

Math Is Fun Forum

#1 2008-10-29 08:40:42

integration

#2 2008-10-29 09:15:12

Re: integration

#3 2008-10-30 02:59:26

Re: integration

#4 2008-10-30 03:05:01

Re: integration

#5 2008-10-30 03:12:38

Re: integration

#6 2008-10-30 03:35:09

Re: integration

#7 2008-10-30 04:44:14

Re: integration

#8 2008-10-30 04:49:48

Re: integration

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