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edexcel FP3 june 2013 R paper

I'm doing some very late last minute revision for the retakes of the old specs.

can anyone explain the steps between the 2nd and 3rd rows on the mark scheme for question 5a)

i just can't see the steps i need.

paper and mark scheme location is attached below

https://revisionmaths.com/level-maths/level-maths-past-papers/edexcel-level-maths-past-papers
Reply 1
Avatar for mqb2766
mqb2766
21
Assuming Ive got the right paper / lines, they just split the integrand
(xxx)^(3/2)
as
(xxx)*(xxx)^(1/2)
Is that the question?

Original post by Avshon
I'm doing some very late last minute revision for the retakes of the old specs.

can anyone explain the steps between the 2nd and 3rd rows on the mark scheme for question 5a)

i just can't see the steps i need.

paper and mark scheme location is attached below

https://revisionmaths.com/level-maths/level-maths-past-papers/edexcel-level-maths-past-papers
Reply 2
Avatar for Avshon
Avshon
OP
8
fp3 help.png
I have highlighted the lines I have a problem with.

i cant work out what they have done to the nx^(n-1)(2x-1)(2x-1)^(-1/2)
Original post by mqb2766
Assuming Ive got the right paper / lines, they just split the integrand
(xxx)^(3/2)
as
(xxx)*(xxx)^(1/2)
Is that the question?
Reply 3
Avatar for mqb2766
mqb2766
21
Can't find the 2013 paper :-(, could you attach an image of both the question and the MS?
Original post by Avshon
fp3 help.png
I have highlighted the lines I have a problem with.

i cant work out what they have done to the nx^(n-1)(2x-1)(2x-1)^(-1/2)
Reply 4
Avatar for Avshon
Avshon
OP
8
fp3 help q.pngfp3 help.png
Original post by mqb2766
Can't find the 2013 paper :-(, could you attach an image of both the question and the MS?
fp3 help q.png91.1KB
Reply 5
Avatar for mqb2766
mqb2766
21
Could you attach the MS as well, putting it in the post makes it too blurred.
Original post by Avshon
fp3 help q.pngfp3 help.png
Reply 6
Avatar for Avshon
Avshon
OP
8
here
Original post by mqb2766
Could you attach the MS as well, putting it in the post makes it too blurred.
fp3 help.png108.7KB
Reply 7
Avatar for mqb2766
mqb2766
21
They're doing integration by parts where they're integrating the ()^(-1/2) term "v" and differentiating the x^n term "u".
The second line obviously computes uv and Int(v*du)
The du term is what we want to get a recursive formula x^(n-1), but the v term is ()^(1/2). So split that into (xxx)^(1)*(xxx)^(-1/2). Then split the n(2x-1)^(1) term up into the n2x and -n parts, and take the constants outside each interval. The x*x^(n-1) gives I_n and the x^(n-1) gives I_(n-1).
Reply 8
Avatar for Avshon
Avshon
OP
8
got it now
thank you so much
Original post by mqb2766
They're doing integration by parts where they're integrating the ()^(-1/2) term "v" and differentiating the x^n term "u".
The second line obviously computes uv and Int(v*du)
The du term is what we want to get a recursive formula x^(n-1), but the v term is ()^(1/2). So split that into (xxx)^(1)*(xxx)^(-1/2). Then split the n(2x-1)^(1) term up into the n2x and -n parts, and take the constants outside each interval. The x*x^(n-1) gives I_n and the x^(n-1) gives I_(n-1).

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