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

# Edexcel C3,C4 June 2013 Thread watch

1. (Original post by posthumus)
What answer did you get ?
-3.5
2. (Original post by otrivine)
wow! wait, can i now just use substitution, my integration by parts was the same as urs but do not get then how you or why you considered I?
You don't have to use I, it just makes it easier.

You let I =

You have:

If you notice, you have the same function to be integrated on both sides. So you can replace them both with "I":

Then, because I = (i.e. the question) you just make "I" the subject of the formula.
3. (Original post by otrivine)
they got 12x/y but should there not be a y with 12x?
If it's 12x/y, then it's 12x/y... the question is still doable.
4. (Original post by posthumus)
Its quite unlikely to come up if you ask me - I don't think it has ever before... where did you get the question from ?
It's never come up, no, and a question like that probably won't to be honest. I got it from my maths teacher who got it from a really old (like 10-15 years old) A-Level maths textbook.
5. (Original post by usycool1)
It's never come up, no, and a question like that probably won't to be honest. I got it from my maths teacher who got it from a really old (like 10-15 years old) A-Level maths textbook.
I just realised that the textbook I have has a whole section on integrals of the form and .
6. (Original post by brittanna)
I just realised that the textbook I have has a whole section on integrals of the form and .
I see! I don't have any questions like that in my textbook
8. (Original post by samfreak)
Nah solutionbank is right

(Original post by brittanna)
I just realised that the textbook I have has a whole section on integrals of the form and .
which book you using i dont see it in the green book?
9. (Original post by samfreak)
No.

Notice that the limits of the integral changed.

10. (Original post by justinawe)
No.

Notice that the limits of the integral changed.

Hi, in connecting rates, what is r/h in triangle? is this a formula for finiding what ? thanks
11. (Original post by justinawe)
No.

Notice that the limits of the integral changed.

where have they chnaged?
12. (Original post by QwertyG)
Nah solutionbank is right

which book you using i dont see it in the green book?
I have an older one I think. It says:
Advanced Maths A2 core for edexcel.

It's this one here:

13. (Original post by samfreak)
where have they chnaged?
On the second line (the line beginning with A_1=) it was whereas on the line after it was
14. (Original post by brittanna)
On the second line (the line beginning with A_1=) it was whereas on the line after it was
Hi In cone why do we use r/h ? and what is it in triangle
15. (Original post by otrivine)
Hi In cone why do we use r/h ? and what is it in triangle
I don't think I know what you mean. Have you get an example of a question that uses it?
16. *cries*
had to do a C4 paper as a test in class, i knew what paper it was gona be and got 51%

ha hahahalgnsrlkgnsrin
17. (Original post by brittanna)
I don't think I know what you mean. Have you get an example of a question that uses it?
http://www.examsolutions.net/maths-r...tutorial-3.php

this tutor uses that r/h formula? thanks
18. (Original post by otrivine)
http://www.examsolutions.net/maths-r...tutorial-3.php

this tutor uses that r/h formula? thanks
It's just the way similar shapes are defined (from GCSE). So in this case, the ratio of the height to the radius is the same in each of the triangles he looked at. I guess triangles would be the same as it was a triangle he was looking at in the cone question.
19. (Original post by brittanna)
It's just the way similar shapes are defined (from GCSE). So in this case, the ratio of the height to the radius is the same in each of the triangles he looked at. I guess triangles would be the same as it was a triangle he was looking at in the cone question.
oh so what does r/h calculate ?
20. (Original post by otrivine)
oh so what does r/h calculate ?
It's just the ratio of of the length and height of the triangle, it doesn't represent any physical quantity. But because the two triangles are mathematically similar, it gives us an extra equation we can use.

Do you remember doing similar triangles at GCSE?

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: September 24, 2013
Today on TSR

### How much will your degree earn you?

Find out where yours ranks...

### I do my boyfriend's uni assignments

Poll
Useful resources

Can you help? Study help unanswered threadsStudy Help rules and posting guidelinesLaTex guide for writing equations on TSR

## Groups associated with this forum:

View associated groups

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