You are Here: Home >< Maths

# Edexcel A2 C4 Mathematics June 2015 - Official Thread watch

1. DI/DT=-16(0.5)^t(ln(0.5))
Sub in t=3
So it becomes -2ln0.5
Which is the same as ln(0.5^-2)
Which is equal to ln4

Posted from TSR Mobile
2. With integration am i right in thinking that the integral of ( k f'(x) ) / f(x) = K ln(f(x))

So the integral 6x2 / X3+5 = 2ln(x3+5)
3. (Original post by raypalmer)
DI/DT=-16(0.5)^t(ln(0.5))
Sub in t=3
So it becomes -2ln0.5
Which is the same as ln(0.5^-2)
Which is equal to ln4

Posted from TSR Mobile
I'm currently stuck on this question too!!
Can you please explain to me what you have done?
4. (Original post by Alice Moody)
oh....sorry thought the first bit was saying about using a substitute

sorry
it's fine how would you integrate that?
5. (Original post by raypalmer)
DI/DT=-16(0.5)^t(ln(0.5))
Sub in t=3
So it becomes -2ln0.5
Which is the same as ln(0.5^-2)
Which is equal to ln4

Posted from TSR Mobile
thanks!
6. (Original post by manlikem)
it's fine how would you integrate that?
Whats the equation again?
7. (Original post by frozo123)
thanks!
No worries

Posted from TSR Mobile
8. (Original post by manlikem)
what do you mean? The question is just integrate sinx cos^3 x dx
Im tempted to say by parts?
i will have a go on paper and let ya know
9. (Original post by Alice Moody)
I'm currently stuck on this question too!!
Can you please explain to me what you have done?
First differentiate, differentiating a^x gives u a^xlna, then sub in t

Posted from TSR Mobile
10. (Original post by tiny hobbit)
Have you done the R papers for June 2013 and June 2014? Or the C4 questions from the IAL C34 papers? They're written by the same team as write the ordinary ones.
ah no not yet, I've encountered some questions from June 2014 R and 2013R and some from IAL in the gold papers but I haven't gone through an actual replacement paper or a IAL paper yet... I've just done the 3rd gold paper and am planning to finish the 4th one... I will probably have time for one more paper on top of that... which one do you recommend from here? thanks
11. (Original post by raypalmer)
First differentiate, differentiating a^x gives u a^xlna, then sub in t

Posted from TSR Mobile
EDIT: Nevermind, sorted it!
12. (Original post by Alice Moody)
Whats the equation again?
13. (Original post by raypalmer)
First differentiate, differentiating a^x gives u a^xlna, then sub in t

Posted from TSR Mobile
OOOOOHHHHH!!!!!!!!!!!! is that c2 log laws at first?
14. (Original post by manlikem)
Ill have a go and get back to ya
15. (Original post by Leking9)
For real!
I hate consecutive exams... especially when it's 2 of my most important ones... (applying for econ at uni)....

If only there was a day in between, or even if the econ unit 3 was in AM rather than PM...
Ah well... what's done is done.... I dont think I'm getting that A*...
time to just focus on C4 and then beg the maths Gods to make it low enough for me to get an A in C3...
16. When finding the shortest distance from the point to a line, how can you assume that a right angle is made between the point and the line?
17. (Original post by joe1545)
Slightly reassuring the the last paper I've just done before I do the real thing was the Jan 2014 paper, and managed to get 98UMS.. If only tomorrow goes that well.
Nice! don't you mean June 2014? I don't think theres a Jan 2014...
18. (Original post by Alice Moody)
OOOOOHHHHH!!!!!!!!!!!! is that c2 log laws at first?
If , then ; thus by implicit differentiation:
19. (Original post by arsenalfc97)
When finding the shortest distance from the point to a line, how can you assume that a right angle is made between the point and the line?
I got an idea for you
stand 2m away from your wall
step 1
Walk forward ( perpendicular ) until your hand bangs against the wall

after that
Stand in the exact same spot, but try touching the wall at the end of the room

which one took less less time and distance?
20. (Original post by Bustamove)
How good are the gold papers in preparation for C4? I've done 2 today and plan to finish the other 2 by the end of today.... I've done all the papers from jan 2009 - june 14.... anyone got anymore suggestions to what other papers I should look at?
I probably have time for one more paper along with the 2 last gold papers that I'm planning to do.. wanna get a good sleep before tomorrow to reduce my chances of making stupid mistakes...
Can you please explain how to do part b to me? ANd hwo do you get that x = 0.1?
https://a086a5a2f39bda93734c56a63fab...%20Edexcel.pdf
number 4

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

### The most controversial member on TSR?

Who do you think it is...

### Is confrontation required?

Discussions on TSR

• Latest
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
Discussions on TSR

• Latest

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