You are Here: Home >< Maths

# Edexcel A2 C4 Mathematics June 2015 - Official Thread watch

1. (Original post by Maham88)
thats what i did but are they doing here page 9 https://a48aca6bcd82b5ada594d7397b73...%20koli248.pdf
I think they converted it to 2cos2ysin2y then used factor formulae
2. (Original post by frozo123)
I think they converted it to 2cos2ysin2y then used factor formulae
No they just looked at part a since it gives you it there
3. (Original post by anonwinner)
Look at part a of that question... It literally gives you it
oh right , thanks
4. (Original post by ridirahman)
As long as there isn't a really big difficult vectors question I'll be fine
I hope the differential equation is like Q2 and then vector question is Q7
lol that will make my day
5. (Original post by 286001)
Can someone help me on part iiI know that when two lines are parallel a.b=|a||b| but then I have too many unknowns Attachment 429579
Which paper is this?
6. (Original post by studentwiz)
do you think the paper would be harder this year?
To you question about integration by recognition its sort of like this

{ <- pretend that's an integral sign

{ [f'(x)][f(x)]^n = [f(x)^(n+1)]/(n+1)

its difficult to explain but you look for 'reverse of a differentiation'

if you differentiated a function

[f(x)]^n -> n[f'(x)][f(x)]^(n-1)

and you have to look for the reverse when integrating, thats the best i can explain it but it's not an easy concept to show in the chat :L
7. (Original post by Maham88)
oh right , thanks
No problem, always keep your eye out for things like that
8. (Original post by 286001)
Can someone help me on part iiI know that when two lines are parallel a.b=|a||b| but then I have too many unknowns Attachment 429579
The line that OA is a part of has the same direction vector as l2
Since OA goes through O, you can thus say OA = k(direction vector)
Then you just solve for the distance
9. alright **** this... lets just get this over a done with... lets just focus on C4 and try not fail too hard...
good luck everyone
10. (Original post by frozo123)
I hope the differential equation is like Q2 and then vector question is Q7
lol that will make my day
that would kill me Q7's are usually hard and I can't do any hard vectors Q's
I just hope there are no more than 8 questions unlike the c3 exam
11. (Original post by Humbers)
To you question about integration by recognition its sort of like this

{ <- pretend that's an integral sign

{ [f'(x)][f(x)]^n = [f(x)^(n+1)]/(n+1)

its difficult to explain but you look for 'reverse of a differentiation'

if you differentiated a function

[f(x)]^n -> n[f'(x)][f(x)]^(n-1)

and you have to look for the reverse when integrating, thats the best i can explain it but it's not an easy concept to show in the chat :L
i sort of see your point, what method do you usually use?
12. when we are finding the volume of a cone is the length the r value or the width the r value??
13. (Original post by studentwiz)
i sort of see your point, what method do you usually use?
you have to recognise which method you'll have to use hence the name integration by recognition
14. (Original post by studentwiz)
when we are finding the volume of a cone is the length the r value or the width the r value??
r is the radius of the circle and h is the slanted height of the cone.
15. (Original post by studentwiz)
i sort of see your point, what method do you usually use?
If i can use recognition then i'll use that because its the fastest
I will only ever use substitution when the question tells me to
and if i cant be recognized i'll use by parts

heres an example of recognition that might make more sense

16. (Original post by 286001)
Can someone help me on part iiI know that when two lines are parallel a.b=|a||b| but then I have too many unknowns Attachment 429579
No it's not, what have you done so far?
17. Can anyone give me an example of a trig integration by parts where I have to sub it back in at the end? Don't think I've come across one.
18. Alright, let's do this. Good luck guys, off to school.
19. Okay, good luck guys! Hope the paper is easy since c3 was hard af. Off to school.
20. (Original post by studentwiz)
when we are finding the volume of a cone is the length the r value or the width the r value??

r = radius so it will be the width of the base i guess

if you're asking because of that volume of revolution question in the recent paper (can't remember which) r = the y value

Just think about how it will look when rotated and its the radius of the cone formed

### 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: April 20, 2016
Today on TSR

### Exam Jam 2018

Join thousands of students this half term

### Solo - A Star Wars Story

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