You are Here: Home >< Maths

# Core 3 - Integration Help! Watch

1. Right, I've differentiated part a) which has given me lnx + 1. However I don't know how to use this or where to start with part b), the integration bit.

http://img96.imageshack.us/img96/9764/integrationr.png

Could anyone help me out please?

Much appreciated!

2. so, integrating both sides w.r.t. x:

so
3. (Original post by Pheylan)

so, integrating both sides w.r.t. x:

so
Sorry, I still don't really understand what is actually going on there. That's pretty much what it says in the mark scheme and I just need it explained really.
4. (Original post by themagicpiano)
Sorry, I still don't really understand what is actually going on there. That's pretty much what it says in the mark scheme and I just need it explained really.
well from the first part, you know that

so if you integrate both sides of that equation (which you're allowed to do), you get

subtract from both sides to get on its own:

then you can simplify the RHS. (remember that and )
5. (Original post by Pheylan)
well from the first part, you know that

so if you integrate both sides of that equation (which you're allowed to do), you get

subtract from both sides to get on its own:

then you can simplify the RHS. (remember that and )
Ah, that makes sense. Thank you for your help!
6. (Original post by Pheylan)
well from the first part, you know that

so if you integrate both sides of that equation (which you're allowed to do), you get

subtract from both sides to get on its own:

then you can simplify the RHS. (remember that and )
Out of interest, since it says 'Hence, or otherwise find', which method could be used to find the integral if I didn't do part a)?

7. (Original post by themagicpiano)
Out of interest, since it says 'Hence, or otherwise find', which method could be used to find the integral if I didn't do part a)?
have you learnt integration by parts yet? if so:

use IBP with u=lnx and dv/dx=1

(Original post by themagicpiano)
no problem

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: December 28, 2010
Today on TSR

### Degrees to get rich!

... and the ones that won't

### Women equal with Men?

Discussions on TSR

• Latest
• ## See more of what you like on The Student Room

You can personalise what you see on TSR. Tell us a little about yourself to get started.

• 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

## Groups associated with this forum:

View associated groups
Discussions on TSR

• Latest
• ## See more of what you like on The Student Room

You can personalise what you see on TSR. Tell us a little about yourself to get started.

• The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE

Reputation gems: You get these gems as you gain rep from other members for making good contributions and giving helpful advice.