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2016 c34 ial

Hi so I'm currently doing this paper and am confused with the mark scheme

Page 10 : https://0025309b76bc88a0e4c3444acd0336108aeab3fa.googledrive.com/host/0B1ZiqBksUHNYOVV4M2RndmNyUkU/Edexcel%20C34%20-%20January%202016%20(IAL)%20Model%20Answers.pdf

How does

3lnx−2ln(3x−2)=x33x−23lnx - 2ln(3x-2) = \dfrac{x^3}{3x-2} ?

Shouldn't it be x3(3x−2)2\dfrac{x^{3}}{(3x-2)^{2}} ?

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You are right. Mark scheme is wrong!
(edited 7 years ago)
Reply 2
Avatar for edothero
edothero
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15
Original post by Math12345
You are right. Mark scheme is wrong!


Though so, the answer I got was

Ax3e2x−1(3x−2)2\dfrac{Ax^{3}}{e^{2x^{-1}}(3x-2)^{2}}

Which is the same as the mark scheme except I have (3x−2)2(3x-2)^{2} :tongue:
Original post by edothero
Though so, the answer I got was

Ax3e2x−1(3x−2)2\dfrac{Ax^{3}}{e^{2x^{-1}}(3x-2)^{2}}

Which is the same as the mark scheme except I have (3x−2)2(3x-2)^{2} :tongue:


Wolfram agrees with you (constant A replaced with constant c1)
https://www.wolframalpha.com/input/?i=x^2%283x-2%29dy%2Fdx%3Dy%283x^2-4%29
Reply 4
Avatar for Zacken
Zacken
22
Original post by edothero
Hi so I'm currently doing this paper and am confused with the mark scheme

Page 10 : https://0025309b76bc88a0e4c3444acd0336108aeab3fa.googledrive.com/host/0B1ZiqBksUHNYOVV4M2RndmNyUkU/Edexcel%20C34%20-%20January%202016%20(IAL)%20Model%20Answers.pdf

How does

3lnx−2ln(3x−2)=x33x−23lnx - 2ln(3x-2) = \dfrac{x^3}{3x-2} ?

Shouldn't it be x3(3x−2)2\dfrac{x^{3}}{(3x-2)^{2}} ?


Yeah, you're right.

This was my paper! :biggrin:
Reply 5
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edothero
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15
Original post by Zacken
Yeah, you're right.

This was my paper! :biggrin:


I hope my paper in June is of the same difficulty :tongue:

How did you do on this paper?

Just finished, got 119/125 :biggrin:
Nothing too challenging; didn't know how to do 4b. :rofl:

Made a rookie error on the second part of 13b so I gave myself 3/6

Spoiler


And was unable to do 13d, I don't understand how the answer was obtained though? Mind explaining?
Reply 6
Avatar for Zacken
Zacken
22
Original post by edothero
I hope my paper in June is of the same difficulty :tongue:

How did you do on this paper?

Just finished, got 119/125 :biggrin:
Nothing too challenging; didn't know how to do 4b. :rofl:

Made a rookie error on the second part of 13b so I gave myself 3/6

Spoiler

And was unable to do 13d, I don't understand how the answer was obtained though? Mind explaining?


I gave my answer to Q3 as 9+6ln⁡38\frac{9 + 6\ln 3}{8} instead of 9+ln⁡368\frac{9 + \ln 3^6}{8} and lost a mark for that, so 124/125 = 198/200 UMS. Super annoying.

Q13 (d) just wants you to appreciate that if t runs between -pi/2 and pi/2 then sin t runs between -1 and 1 so 2 sin t runs between -2 and 2, but y = 2 sin t, so y runs between -2 and 2. Which is precisely what -k < y < k says when k=2.
Reply 7
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edothero
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15
Original post by Zacken
I gave my answer to Q3 as 9+6ln⁡38\frac{9 + 6\ln 3}{8} instead of 9+ln⁡368\frac{9 + \ln 3^6}{8} and lost a mark for that, so 124/125 = 198/200 UMS. Super annoying.

Q13 (d) just wants you to appreciate that if t runs between -pi/2 and pi/2 then sin t runs between -1 and 1 so 2 sin t runs between -2 and 2, but y = 2 sin t, so y runs between -2 and 2. Which is precisely what -k < y < k says when k=2.


LOL you had one job :clap2:

In hindsight that makes sense and is quite obvious, oh well :colonhash:

Thanks, and well done on your results, I need not bother to ask for the rest of your results as you probably got the 95-100 UMS in the rest
What will you be taking in the summer? Or in a couple weeks/month, should I say.
Reply 8
Avatar for Zacken
Zacken
22
Original post by edothero
LOL you had one job :clap2:

In hindsight that makes sense and is quite obvious, oh well :colonhash:

Thanks, and well done on your results, I need not bother to ask for the rest of your results as you probably got the 95-100 UMS in the rest
What will you be taking in the summer? Or in a couple weeks/month, should I say.


Yeaaaah, it's just that it's not even technically a mistake and my form looks so much neater that pisses me off about it. :rofl:

I'll be doing FP2/3, S3 and Physics 4-6. I sat the majority of my exams in Jan, so that's outta the way. I presume you're doing FP2/3 alongside me as well as some of the applied modules and C34? (and STEP)
Reply 9
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edothero
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15
Original post by Zacken
Yeaaaah, it's just that it's not even technically a mistake and my form looks so much neater that pisses me off about it. :rofl:

I'll be doing FP2/3, S3 and Physics 4-6. I sat the majority of my exams in Jan, so that's outta the way. I presume you're doing FP2/3 alongside me as well as some of the applied modules and C34? (and STEP)


Yeah I know what you mean :laugh:

Yep, FP2/3, C3/4 (I'm UK based), S2/M2 and STEP I and II for banter. As I don't need STEP to get into Uni :biggrin:.
Reply 10
Avatar for Zacken
Zacken
22
Original post by edothero
Yeah I know what you mean :laugh:

Yep, FP2/3, C3/4 (I'm UK based), S2/M2 and STEP I and II for banter. As I don't need STEP to get into Uni :biggrin:.


Warwick, right? :biggrin:
Reply 11
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edothero
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15
Original post by Zacken
Warwick, right? :biggrin:


Not quite, I will be studying Computer Science at uni as that is what interests me the most :biggrin:.
Though I will miss pure Maths, a lot :cry2:
Reply 12
Avatar for Zacken
Zacken
22
Original post by edothero
Not quite, I will be studying Computer Science at uni as that is what interests me the most :biggrin:.
Though I will miss pure Maths, a lot :cry2:


Oh, wow! Where? :biggrin:

Tbf, Comp Sci has quite a bit of pure maths, so you're in for a treat. :woo:
Original post by edothero
I hope my paper in June is of the same difficulty :tongue:


I honestly hope it's a bit harder then this, and moderate overall.

The grade boundary of Jan 2016 was punishing.

115ish for full UMS would be decent.
Reply 14
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edothero
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15
Original post by Zacken
Oh, wow! Where? :biggrin:

Tbf, Comp Sci has quite a bit of pure maths, so you're in for a treat. :woo:


KCL. My FM teacher didn't want to predict me an A* even though I averaged 277 in AS so I got rejected by Imperial :frown:
And UCL ran out of places by the time they reached my application.. (made me wait 6 months and 7 days)

Yeah I will be taking a couple modules (some compolsury and some optional) on AI which look very Maths-y.
My degree includes a year in industry so if I can line up a good job in the heart of London, I could potentially be set for when I graduate.

Or ya'know, I could just do a year abroad and have the time of my life :laugh:
Reply 15
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edothero
OP
15
Original post by SaadKaleem
I honestly hope it's a bit harder then this, and moderate overall.

The grade boundary of Jan 2016 was punishing.

115ish for full UMS would be decent.


Yeah I just want an average paper with average 67-68 for A* boundaries, nothing too easy as one slip up could cost you the A*.

S2 is the worst, all the individual questions are worth like 3 marks at least, and it's usually 71 to get an A* :rofl:
https://a086a5a2f39bda93734c56a63fab1d7be0a9ba38.googledrive.com/host/0B1ZiqBksUHNYQXE5T2xiNDBRd2s/June%202015%20(IAL)%20QP%20-%20C34%20Edexcel.pdf

Hi. How do I do 5(ii) and 13 c and d? I'm struggling with this thing badly!
Reply 17
Avatar for Zacken
Zacken
22
Original post by sabahshahed294


In the future, please post your own thread instead of hijacking others. :smile:

Note that t+1t=1+1t\frac{t+1}{t} = 1 + \frac{1}{t} so if you integrate that, you get t+ln⁡tt + \ln t, if you plug in limits, you get:

2a+ln⁡(2a)−a−ln⁡a=a+ln⁡2=ln⁡7  ⟺  a=ln⁡7−ln⁡22a + \ln (2a) - a - \ln a = a + \ln 2 = \ln 7 \iff a = \ln 7 - \ln 2
Original post by Zacken
In the future, please post your own thread instead of hijacking others. :smile:

Note that t+1t=1+1t\frac{t+1}{t} = 1 + \frac{1}{t} so if you integrate that, you get t+ln⁡tt + \ln t, if you plug in limits, you get:

2a+ln⁡(2a)−a−ln⁡a=a+ln⁡2=ln⁡7  ⟺  a=ln⁡7−ln⁡22a + \ln (2a) - a - \ln a = a + \ln 2 = \ln 7 \iff a = \ln 7 - \ln 2

I'm sorry but I didn't get you lol? I understood the working but own thread?
Reply 19
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Zacken
22
Original post by sabahshahed294
I'm sorry but I didn't get you lol? I understood the working but own thread?


You should create your own thread by clicking "compose thread" in the forum and ask your question there, not use someone elses thread to ask your question. You may want to read up the FAQ! :smile:

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