# Edexcel maths A level paper 2 sample

#1
I’m doing question 16 on the edexcel paper 2 sample paper and it integrates 4/(11-2P) dP to -2ln(11-2P).

I thought that it would integrate to 4ln(11-2P). Don’t know if I’m missing something really obvious here??
0
4 weeks ago
#2
(Original post by cata03)
I’m doing question 16 on the edexcel paper 2 sample paper and it integrates 4/(11-2P) dP to -2ln(11-2P).

I thought that it would integrate to 4ln(11-2P). Don’t know if I’m missing something really obvious here??
try differentiating 4ln(11-2P) and what do you get?
0
#3
(Original post by gdunne42)
try differentiating 4ln(11-2P) and what do you get?
Ah yes i see where I went wrong now! Is there a technique you can use to integrate 4/(11-2p) or did you just do it by inspection?
thanks so much!
1
4 weeks ago
#4
(Original post by cata03)
Ah yes i see where I went wrong now! Is there a technique you can use to integrate 4/(11-2p) or did you just do it by inspection?
thanks so much!
Substitution u=11-2p would also work.
0
4 weeks ago
#5
(Original post by cata03)
Ah yes i see where I went wrong now! Is there a technique you can use to integrate 4/(11-2p) or did you just do it by inspection?
thanks so much!
Yes I'd generally do these by inspection.
Love that word 'inspection' makes it sound much more respectable than take an educated guess and see what is wrong with your guess and tweak it.
0
4 weeks ago
#6
(Original post by cata03)
Ah yes i see where I went wrong now! Is there a technique you can use to integrate 4/(11-2p) or did you just do it by inspection?
thanks so much!
integral(f’(x)/f(x)) = ln(f(x))

Good formula to know for all fraction integrals

so just rearrange it to a form where it’s a constant multiplier * f’(x)/f(x), in this case -2 * (-2/11-2p) and integrate!

Specific easy to remember case of this for linear denominator and constant numerator: integral(a/bx+d) = a/b ln(bx+d)
0
X

new posts
Back
to top
Latest
My Feed

### Oops, nobody has postedin the last few hours.

Why not re-start the conversation?

see more

### See more of what you like onThe Student Room

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

### Poll

Join the discussion

#### Year 12s - where are you at with making decisions about university?

I’ve chosen my course and my university (19)
32.2%
I’ve chosen my course and shortlisted some universities (22)
37.29%
I’ve chosen my course, but not any universities (2)
3.39%
I’ve chosen my university, but not my course (3)
5.08%
I’ve shortlisted some universities, but not my course (4)
6.78%
I’m starting to consider my university options (7)
11.86%
I haven’t started thinking about university yet (1)
1.69%
I’m not planning on going to university (1)
1.69%