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# core maths c12 10 jan 2017 watch

1. (Original post by mr.holmes)
i got 2 values for y since it will be a quadratic equation. i basically solved it by substitution since the gave as the what is Y is equal to.
2. (Original post by Sumaiyya1999)
The ans for the part a wasnt y/2 it was y - 2 and after solving i got 3 for y and 27 for x

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Well either you messed up in part A or I did lol. I probably did cuz I was getting the same y expression in both questions.
3. (Original post by mr.holmes)
i got 2 values for y since it will be a quadratic equation. i basically solved it by substitution since the gave as the what is Y is equal to.
4. (Original post by Fasih178)
Well either you messed up in part A or I did lol. I probably did cuz I was getting the same y expression in both questions.
but did you get a quadratic equation for it?
5. guys I thought there was no more January papers
6. (Original post by Fasih178)
Well either you messed up in part A or I did lol. I probably did cuz I was getting the same y expression in both questions.
I actually opened up the log so for me log3(x/9)= log3(x) - log3(9) since log3(x)=y and log3(9)= 2 so I got y-2
7. (Original post by Emz99)
guys I thought there was no more January papers
There are no jan papers for gce
C12 papers are only for IAL
8. (Original post by mr.holmes)
but did you get a quadratic equation for it?
Nope, the question said 'hence or otherwise' I chose the otherwise part since I was pretty dubious about my answer to part A. But that might be why I didn't get a quadratic equation. At the end of the day there was only one solution and that was 81.
9. (Original post by Sumaiyya1999)
I actually opened up the log so for me log3(x/9)= log3(x) - log3(9) since log3(x)=y and log3(9)= 2 so I got y-2
That's definitely the correct answer. Why on earth didn't I think of that dammit
10. But shouldn't u get a quadratic equation if u choose otherwise cuz it was give 2log3 (x) which becomes log3 (×^2) so u end up with a quadratic equation in x

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11. for tan ( Qtheta -10) i got 1.3 and 181.3 ...

while for barrels i got 39600.. litres.

for 1 barrel was 1970 litres..
12. (Original post by Fasih178)
Nope, the question said 'hence or otherwise' I chose the otherwise part since I was pretty dubious about my answer to part A. But that might be why I didn't get a quadratic equation. At the end of the day there was only one solution and that was 81.
but they asked you to find the value for x or what exactly?
i thought we use the y for substituting in the equation
13. I actually got 1.3 and 91.3
And dor the barrels i got 34480 litres

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14. (Original post by Sumaiyya1999)
But shouldn't u get a quadratic equation if u choose otherwise cuz it was give 2log3 (x) which becomes log3 (×^2) so u end up with a quadratic equation in x

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Umm it was 2log3 (x/9) wasn't it? And the other term was log3 (√x) I recall.
15. how is it possible to get 91.3

not possible because tan is positive in 3rd quadrant and 3rd quadrant is angle greater than 180.

i wrote (180 + 11.30) minus 10

to get 181.3
16. Yes i just remembered guess i am gonna lose 1 or 2 marks for it

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17. (Original post by Sumaiyya1999)
Yes i just remembered guess i am gonna lose 1 or 2 marks for it

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18. (Original post by Fasih178)
Umm it was 2log3 (x/9) wasn't it? And the other term was log3 (√x) I recall.
O yes but that way way also u should get a quadratic equation cuz (x/9)^2 is x^2/9^2

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19. (Original post by Fasih178)
Umm it was 2log3 (x/9) wasn't it? And the other term was log3 (√x) I recall.
yes and what was y
the one given in the question?
20. (Original post by mr.holmes)
yes and what was y
the one given in the question?
i got y= 1/5 and x= 81...
and i think these are correct.. becuz i confirmed it with ma fellows

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