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OCR (not MEI) C1 - Wednesday 13th May 2015 watch

1. (Original post by gabby07)
Hi can I just briefly turn attention to a C2 question I'm having a bit of trouble with (I know it ought to be easy, and I'm sure it is...!)

Can anyone help me out with this:

7x = 2x+1

Solve for x.

So far, I've got up to here:
log7x = log2x+1
xlog7 = (x+1)log2

I have no idea where to go from here! Normally you can just divide by logs to find the x solution and then act as necessary but the way to do this isn't appearing in my head! Thanks!!
xlog7 = (x + 1)log2
(log7)/(log2) = (x + 1)/x
(log7)/(log2) = 1 + 1/x
(log7)/(log2) - 1 = 1/x
x = 1/((log7)/log2) - 1)

Probably wrong... It's been a long year since I did any C2.
I'm pretty sure there's a (Not MEI) OCR C2 post somewhere on TSR for you
I think it was out of 5...

2 for finding 3 points
2 for finding base + perpendicular height
1 for final answer (40 square units)

(Probably)
It was only 4 marks.

I would say M1, 2 for the points, since this was the main brief of the question.
M3 for base and height
3. (Original post by Whittick)
It was 100% 40 square units.

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Would you get marks for mentioning the distance formula?
What points did you get?
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How are you sure it was 40 square units .Everyone seems to have different answers for that question.
It definitely is. If you scroll back there are many people who have proved why popular answers such as 50 and 20root5 are wrong.
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Would you get marks for mentioning the distance formula?
What points did you get?
I'm not sure but if you got the correct lengths of the 3 sides then I would have thought so...

And I substituted y=0 into the equation of the circle and the tangent, then did 3 lots of the distance formula and a simple half base-height to get 40 units square haha
6. Tbh sorry no dont remember any.. Reckon high boundaries as it wasnt too hard
It definitely is. If you scroll back there are many people who have proved why popular answers such as 50 and 20root5 are wrong.

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Ah damn.I hope I pick at least 1 marl from that question.I need to get a high A in this C1 exam .
8. (Original post by gabby07)
It was only 4 marks.

I would say M1, 2 for the points, since this was the main brief of the question.
M3 for base and height
Oh, ok sorry. Yeah; you're quite right then.
9. (Original post by chloe-jessica)
From this, expand the right to get:
xlog7 = xlog2 + log2

Collect like terms:
xlog7 - xlog2 = log2

Factorise:
x (log7 - log2) = log 2

Use log rule with subtracting -> dividing:
x (log(7/2)) = log 2

Divide:
x = log2 / log(7/2)

Hope that helped
Thank you!
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Ah damn.I hope I pick at least 1 marl from that question.I need to get a high A in this C1 exam .
Are you resitting then?

Also if those are the only marks you dropped then 69/72 is almost definitely 90UMS at least.
11. (Original post by Whittick)
It was 100% 40 square units.
Yeah it was I got it wrong though 😒
xlog7 = (x + 1)log2
(log7)/(log2) = (x + 1)/x
(log7)/(log2) = 1 + 1/x
(log7)/(log2) - 1 = 1/x
x = 1/((log7)/log2) - 1)

Probably wrong... It's been a long year since I did any C2.
I'm pretty sure there's a (Not MEI) OCR C2 post somewhere on TSR for you
Thanks
Oh, ok sorry. Yeah; you're quite right then.
Haha! No fault of yours!! I find it incredible how people remember everything about the exam paper
Are you resitting then?

Also if those are the only marks you dropped then 69/72 is almost definitely 90UMS at least.

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Nah,I think I got wrong answer for k and forgot to mention stretch for the graph.
Apart from that,I pretty sure I got full marks on everything else.
Oh, ok sorry. Yeah; you're quite right then.
it was actually 3 marks
16. for question 8iii i worked it out 2 ways and got two different answers - one of which was correct. What will they do about that will they give me any marks at all?
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Nah,I think I got wrong answer for k and forgot to mention stretch for the graph.
Apart from that,I pretty sure I got full marks on everything else.

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18. I wrote 40 but no units squared would i lose marks
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Nah,I think I got wrong answer for k and forgot to mention stretch for the graph.
Apart from that,I pretty sure I got full marks on everything else.
Did you get the scale factor (1/3) ? If so then that's probably going to be a mid-low A
20. Is there an unofficial markschem

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