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# c4 integration help watch

1. http://qualifications.pearson.com/co...e_20150612.pdf

how would I do part 13C, im confused
2. Which question?
3. (Original post by imran_)
http://qualifications.pearson.com/co...e_20150612.pdf

how would I do part C, im confused
Which question?

4. (Original post by NotNotBatman)
Which question?
13c sorry
5. (Original post by notnek)
Which question?

13c, its asking to work it out by parts but I have no clue where to start. What I did first was bring the 2 down to get 2lnx and solved from there but its wrong
6. Multiply the natural log by 1.
7. (Original post by imran_)
13c, its asking to work it out by parts but I have no clue where to start. What I did first was bring the 2 down to get 2lnx and solved from there but its wrong
Try integrating by calling it 1*(Lnx)^2 with 1 being your v'.
8. (Original post by imran_)
http://qualifications.pearson.com/co...e_20150612.pdf

how would I do part 13C, im confused
for intergration by parts use the formula. integral of v du/dx= uv + integral of v du/dx and because it's a ln need to make dv/dx 1 and u (lnx)^2 hope that helps
9. So, when you have a natural log function, ln[f(x)], you can integrate it by parts using 1 x ln[f(x)] and choosing your u and dv.
10. (Original post by NotNotBatman)
Multiply the natural log by 1.
sorry im confused, i made u=lnx and solved from there and got the correct answer but how would you do your method?
11. (Original post by NotNotBatman)
So, when you have a natural log function, ln[f(x)], you can integrate it by parts using 1 x ln[f(x)] and choosing your u and dv.
Are you Batman?
12. (Original post by NotNotBatman)
So, when you have a natural log function, ln[f(x)], you can integrate it by parts using 1 x ln[f(x)] and choosing your u and dv.
okay ill give it a go!
13. (Original post by imran_)
sorry im confused, i made u=lnx and solved from there and got the correct answer but how would you do your method?
Latex isn't working for me, so it's a bit hard to explain, I'd basically do it the way examsolutions does in this video , except making u =(lnx)^2 .

(Original post by eden3)
Are you Batman?
Spoiler:
Show
Well, I'm not not batman.
14. (Original post by NotNotBatman)
So, when you have a natural log function, ln[f(x)], you can integrate it by parts using 1 x ln[f(x)] and choosing your u and dv.
Well I don't think you can extend the result to since that will only work if you can integrate
15. (Original post by NotNotBatman)
Latex isn't working for me, so it's a bit hard to explain, I'd basically do it the way examsolutions does in this video , except making u =(lnx)^2 .
Spoiler:
Show
Well, I'm not not batman.
okay yeah I just worked it out and gave me the right answer, thanks!
However for part D of the question y=(lnx)^2 if I square it I get (lnx)^4 no?
16. (Original post by eden3)
Are you Batman?
17. (Original post by imran_)
okay yeah I just worked it out and gave me the right answer, thanks!
However for part D of the question y=(lnx)^2 if I square it I get (lnx)^4 no?
No, y= 2-ln(x), part (c) is just to help you for part (d).
18. (Original post by NotNotBatman)
No, y= 2-ln(x), part (c) is just to help you for part (d).
i dont get it. how did you manage to get that
19. (Original post by imran_)
i dont get it. how did you manage to get that
The question says "figure 5 shows a sketch of part of the curve with equation y = 2 - ln x "

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