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C3 intergration by substitution help

How would you intergrate (x+2)/(2x-3)^3 dx
If u=2x-3
(edited 8 years ago)
Original post by toonervoustotalk
How would you intergrate (x+2)/(2x+3)^3 dx
If u=2x-3


Strange substitution choice. Is it not u = 2x+3?

Anyway, what have you tried so far?
Original post by SeanFM
Strange substitution choice. Is it not u = 2x+3?

Anyway, what have you tried so far?


Because i made a mistake in the denominator
Original post by toonervoustotalk
Because i made a mistake in the denominator


What is the mistake?

And what working have you got so far for the question? :smile:
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genius10
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Original post by toonervoustotalk
How would you intergrate (x+2)/(2x+3)^3 dx
If u=2x-3


I think you meant u=2x+3.
Differentiate 2x+3 with respect to x and replace dx with 0.5du

then replace x+2 with some multiple of u (hint)

You should be able to integrate from there...
DSC_0350.jpg
Original post by toonervoustotalk
DSC_0350.jpg


You've replaced dx by du but forgot the /2.

The 1/2 from (u+3)/2 has also disappeared in your substitution.
Original post by SeanFM
You've replaced dx by du but forgot the /2.

The 1/2 from (u+3)/2 has also disappeared in your substitution.


I figured out after i sent it
DSC_0351.jpg
This any better?
I know i somehow have to get ln something as 1/x intergrates to lnx
Original post by toonervoustotalk
I figured out after i sent it
DSC_0351.jpg
This any better?
I know i somehow have to get ln something as 1/x intergrates to lnx


don't forget the du on the RHS. Re-arrange the fraction and integrate. You can take constants outside the integral if you want.

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