# OCR Core 2 Maths: Wednesday 25th May 2016Watch

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3 years ago
#61
(Original post by milliex97)
I got this too
Yes, it is
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3 years ago
#62
(Original post by h3rmit)
I used -1 and 3 as my limits, the stationary point of 1 was a maximum and didn't touch the x axis from inspection

I think I got 6.73, though I may have answers mixed up
Yes I used them thank god! Aah that explains my confusion as I knew there were three roots from the previous question but was confused that only two touched the x axis.
I got 6.73 as the answer to something else I'm pretty sure but the integration question wanted it in exact form, I got 512/15
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3 years ago
#63
For the second last part I got k=1 and a=2.5, is this correct? I basically worked out that half the period was the first two points added together, then went on from there to find a.
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3 years ago
#64
(Original post by milliex97)
Yes I used them thank god! Aah that explains my confusion as I knew there were three roots from the previous question but was confused that only two touched the x axis.
I got 6.73 as the answer to something else I'm pretty sure but the integration question wanted it in exact form, I got 512/15
I too got the answer but at worse you would get -1 for having the correct decimal to 3sf.
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3 years ago
#65
Also yeah N=38 as you can't have a decimal term number but if N=37 then the sum of the arithmetic is less than 1200 (the sum to infinity of the geometric progression). You would only loose one in that case too I believe. The question I found the worst where the first 3 parts of 8. Probably got par i) and iii) correct but I had a total mind blank on ii). I don't know if it's because I did a lot more prep for this exam but I found the C2 paper much easier than the C1.
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3 years ago
#66
What was the answer to part 8ii ????? That stretch transformation of y=3^x-2
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3 years ago
#67
unofficial mark scheme?
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3 years ago
#68
(Original post by milliex97)
What was the answer to part 8ii ????? That stretch transformation of y=3^x-2
3^x-2 is the same as (3^x)(3^-2) as you add the powers so I think it's a stretch SF 1/9 parallel to y axis.
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3 years ago
#69
The answer is + or - root3. Did it after with a maths teacher. Your expansion should of given the coefficient of x^2 to equal 9k^2. When the exam stated this eqauls the constant, they meant the constant of the expasion (the number without any xs, 27) as this stays the same no matter what. So you equate 9k^2 to 27 to get the answer. This also makes sence as the question stated give exact answers.
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3 years ago
#70
(Original post by M12345689)
3^x-2 is the same as (3^x)(3^-2) as you add the powers so I think it's a stretch SF 1/9 parallel to y axis.
Now you put it like that, why didn't I get it😱
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3 years ago
#71
(Original post by black1blade)
For the second last part I got k=1 and a=2.5, is this correct? I basically worked out that half the period was the first two points added together, then went on from there to find a.
With a period of 2pi/a I got a=5/3 and k= root3/2 I think.
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3 years ago
#72
(Original post by gsdfghgfhfg)
What did you get for Q9 A AND K
A=3/5
K=√3/2 ?????? (Root 3, Divided by, 2)
I think thats what i got actually
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3 years ago
#73
(Original post by Sourestdeeds)
With a period of 2pi/a I got a=5/3 and k= root3/2 I think.
Think I did some for the rearranging wrong but hopefully I would have got 1 or 2. Actually I know what happened, didn't add the two pis together when I was working out half the period from the points- douh. That is only 1 actual mistake so hopefully only -1 :P.
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3 years ago
#74
1i) 10
ii ) 5.04
2i) 3/10π
ii)20.4
3i)27+27k+9k^2x^2+k^3x^3
ii) I didn't understand
4i) log3(x^2/x+4)
ii) x=12 and -3 but only 12
5a) 1/2x^4 -x^3+2x^2 -6x+c
bi) 2/a^2 +6/a +4
bii) sum to infinity=4
6i) k=91
ii) sum if the first 16 terms = 978
iii) N=38
7i) (x^2 -4x+3)(x+1)
ii) (x-3)(x-1)(x+1)
iii) proof
iv)512/15
8i) translation along the x axis by +2
ii) stretch in the y axis by 1/9 or 3^-2
iii)0,1/9
iv)x=6.73
v) 9.598 (can't remember how many Sig fig I put it to)
9i) 2π/a
ii)a=5/3 k=(√3)/2
iii) (π/3a) and (4π/3a)
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3 years ago
#75
What was question 1 exactly. Also, what was question 6 I & ii. Thnaks
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3 years ago
#76
(Original post by Shariqameen)
1i) 10
ii ) 5.04
2i) 3/10π
ii)20.4
3i)27+27k+9k^2x^2+k^3x^3
ii) I didn't understand
4i) log3(x^2/x+4)
ii) x=12 and -3 but only 12
5a) 1/2x^4 -x^3+2x^2 -6x+c
bi) 2/a^2 +6/a +4
bii) sum to infinity=4
6i) k=91
ii) sum if the first 16 terms = 978
iii) N=38
7i) (x^2 -4x+3)(x+1)
ii) (x-3)(x-1)(x+1)
iii) proof
iv)512/15
8i) translation along the x axis by +2
ii) stretch in the y axis by 1/9 or 3^-2
iii)0,1/9
iv)x=6.73
v) 9.598 (can't remember how many Sig fig I put it to)
9i) 2π/a
ii)a=5/3 k=(√3)/2
iii) (π/3a) and (4π/3a)
Examiners only allow in the y axis for reflections, and -3 works too if the multiplying two is used a power before logging
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3 years ago
#77
(Original post by jacklfc99)
unofficial mark scheme?

1) 1+1=2
2) 6x5-32
3)21-50=47
cant remember the rest
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3 years ago
#78
(Original post by zzxxDash53xxzz)
1) 1+1=2
2) 6x5-32
3)21-50=47
cant remember the rest
Hope this was some what helpful
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3 years ago
#79
(Original post by groceryboi)
What was question 1 exactly. Also, what was question 6 I & ii. Thnaks
1) i think it was based off knowing the factors of addition something allong the lines of 1+1
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3 years ago
#80
(Original post by h3rmit)
Examiners only allow in the y axis for reflections, and -3 works too if the multiplying two is used a power before logging
You are probally right but when i tried -3 on my calculator it gave me an error and based on my experiance from past papers they only like the single answer that also works on the calculator.And I am not sure about the stretch because that is the first thing that came to my head just hope that its right or i get some marks 😞😞
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