You are Here: Home >< Maths

# Integration by substitution C4 watch

1. How would you integrate x(2x+1)^0.5 using 2x+1 as the substitution (u)?
I have tried making dx= du/2 and then integrating by writing everything in terms of u but can't get the right answer for some reason...

RDKGames
2. (Original post by Uni12345678)
How would you integrate x(2x+1)^0.5 using 2x+1 as the substitution (u)?
I have tried making dx= du/2 and then integrating by writing everything in terms of u but can't get the right answer for some reason...
After making the substitution and simplifying you should get:

It might be worth posting your working.
3. (Original post by SherlockHolmes)
After making the substitution and simplifying you should get:

It might be worth posting your working.
Attachment 610444610446

Sorry went through twice
Attached Images

4. (Original post by Uni12345678)
...
You need to show the working to get to the integral I posted in my first post and not start from there.
5. (Original post by SherlockHolmes)
You need to show the working to get to the integral I posted in my first post and not start from there.
But I understand it already, am I doing anything wrong after that??
6. (Original post by Uni12345678)
But I understand it already, am I doing anything wrong after that??
Oh ok. The rest of your working is fine. Although, you are missing a constant of integration.
7. (Original post by Uni12345678)
But I understand it already, am I doing anything wrong after that??
Forgot the constant of integration.
8. Hahha thank you, but the answers given as 1/15(2x+ 1)^1.5 (3x𝑥 − 1)... +c ofc
9. (Original post by Uni12345678)
Hahha thank you, but the answers given as 1/15(2x+ 1)^1.5 (3x𝑥 − 1)... +c ofc
Yeah just get it in a different form. Start by factoring out and simplify what's inside the bracket.
10. (Original post by RDKGames)
Yeah just get it in a different form. Start by factoring out and simplify what's inside the bracket.
Thank youu

### Related university courses

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: January 10, 2017
Today on TSR

### Edexcel GCSE Maths Unofficial Markscheme

Find out how you've done here

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