x Turn on thread page Beta
 You are Here: Home >< Maths

Integration Help watch

1. k;
2. Well how else can you write ?
3. (Original post by hisname)
How would i integrate x/(x-1)?

I've taken a substitution of u=x-1 and re-written the expression as

(U+1)/U but i don't know what do next i'm guessing its some sort of natural log but i'm not sure.

Spoiler:
Show
split the fraction.

ANS:

_Kar.
4. ';';
5. (Original post by nuodai)
Well how else can you write ?
How exactly would i split the fraction like this

x* 1(x-1) and do integration by parts.
6. (Original post by hisname)
How exactly would i split the fraction like this

x* 1(x-1) and do integration by parts.
You're creating too much work for yourself.

I.e, x/4 + 2y/4 = x+2y/4

You can then split it up again into the same fractions.

When two coefficients share a denominator by the action of addition or subtraction, you can split them up simply by putting the sign in the middle and putting them over separate denominators of the same value.

Think about what you would get in this case.
7. Is this right? you can re-write (U+1)/U as (U/U)+(1/u) or (1+(1/u))

On integrating that gives u+ ln u +c
8. (Original post by hisname)
Is this right? you can re-write (U+1)/U as (U/U)+(1/u) or (1+(1/u))

On integrating that gives u+ ln u +c
Yup, and then you can substitute back to get it in terms of x.
9. Thank you very much for all your help everyone.
10. no you need to differentiate u with respect to x because of the product rule, and multiply it by the function where u is substituted for x to find your integrand
11. (Original post by thievingllama)
no you need to differentiate u with respect to x because of the product rule, and multiply it by the function where u is substituted for x to find your integrand
The product rule definitely doesn't come into this, but if you're referring to the part in integration by substitution where you multiply by du/dx, it doesn't matter in this case since it evaluates to 1.

TSR Support Team

We have a brilliant team of more than 60 Support Team members looking after discussions on The Student Room, helping to make it a fun, safe and useful place to hang out.

This forum is supported by:
Updated: April 2, 2011
Today on TSR

Poll
Useful resources

Maths Forum posting guidelines

Not sure where to post? Read the updated guidelines here

How to use LaTex

Writing equations the easy way

Study habits of A* students

Top tips from students who have already aced their exams

Chat with other maths applicants