xlog7 = (x + 1)log2(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!!
(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
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OCR (not MEI) C1 - Wednesday 13th May 2015 watch
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- 13-05-2015 16:44
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- 13-05-2015 16:44
(Original post by Madhutty)
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)
I would say M1, 2 for the points, since this was the main brief of the question.
M3 for base and height
A1 for answer -
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- 13-05-2015 16:45
(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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- 13-05-2015 16:46
(Original post by Kadak)
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How are you sure it was 40 square units.Everyone seems to have different answers for that question.
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- 13-05-2015 16:46
(Original post by Kadak)
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Would you get marks for mentioning the distance formula?
What points did you get?
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 hahaLast edited by Whittick; 13-05-2015 at 16:47. -
Ubayd53667
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- 13-05-2015 16:47
Tbh sorry no dont remember any.. Reckon high boundaries as it wasnt too hard
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- 13-05-2015 16:48
(Original post by Madhutty)
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.
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- 13-05-2015 16:48
(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
A1 for answer -
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- 13-05-2015 16:49
(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)
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- 13-05-2015 16:49
(Original post by Kadak)
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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.
Also if those are the only marks you dropped then 69/72 is almost definitely 90UMS at least. -
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- 13-05-2015 16:49
(Original post by Whittick)
It was 100% 40 square units. -
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- 13-05-2015 16:49
(Original post by Madhutty)
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 -
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- 13-05-2015 16:51
(Original post by Madhutty)
Oh, ok sorry. Yeah; you're quite right then. -
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- 13-05-2015 16:51
(Original post by Madhutty)
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. -
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- 13-05-2015 16:52
(Original post by Madhutty)
Oh, ok sorry. Yeah; you're quite right then. -
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- 13-05-2015 16:52
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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- 13-05-2015 16:52
(Original post by Kadak)
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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.
Posted from TSR Mobile -
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- 13-05-2015 16:54
I wrote 40 but no units squared would i lose marks
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- 13-05-2015 16:54
(Original post by Kadak)
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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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- 13-05-2015 16:55
Is there an unofficial markschem
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