OCR MEI C3 Maths June 2015

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Reply 520

Sophielouuu

Original post by Leechayy

I'm sorry but I think I'll be taking that :rolleyes:

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Really? Worse than 2/3?

Reply 521

anunoriginaluser

Are there any predictions for the grade boundaries yet? (Specifically A, 90 and 100) People were pretty split in my college, so interested to see opinions.

Reply 522

SH0405

1. (1.107, 4.094) [6]
2. (3(2x-1)^(4/3))/8 + c [4]
3. u = 2x-1, (1/16)(64ln2 - 15) [5]
4. r=h, 1/20pi = 0.0159 [5]
5. gradient = ½ [6]
6. i) x = ½ [2]
ii) x = sqrt(2)/2 [2]
7. i) f(f(x)) = x via substituting in. f^-1(x) = f(x) = (1-x)/(1+x) [3]
ii) g(x) is even since g(-x) = g(x). Symmetrical about the y-axis. [3]
8. i) f^'(x) = 1 - 4/x², f^''(x) = 8/x³which is less than zero when x=-1 and so Q is a maximum point. [7]
ii) Area was 3 take away integral which gave something like...½(15-8ln4) [6]
iii) f(x-1)-1=g(x) so g(x) = (x²-3x)/(x+1) [3]
iv) This is the negative of the previous answer, and yes it's negative, because it asked for the value. [2]
9. i) x = ln3 [2]
ii) x = ln2, y = -1 [4]
iii) The integral came out as negative, but this question asked for the area, so the given answer must be positive; 4 - 3ln3 [5]
iv) f^-1(x) = ln(sqrt(x+1)+2), with the domain as x >= -1 and range as y >= ln2. The sketch of the graph was a reflection in the line y = x, but subject to the 'new' domain and range (i.e. not below ln2). [7]

Please quote me if I have made a mistake...

(edited 8 years ago)

Reply 523

SH0405

Original post by Primus2x

True, luckily I wrote most of the answers twice to make sure, In question one I wrote the coordinates as expressions involving arctangents, exponentials and square roots as well as writing down the approximate decimal coodinates.

Same, I was going to write them in hexadecimal and binary too, but I assumed I should have secured the marks by that point.

Reply 524

anunoriginaluser

Also on (6) (ii) are they likely to accept a bare rt2 / 2 answer without any workings?

Reply 525

SH0405

Unofficial Markscheme; http://www.thestudentroom.co.uk/showthread.php?t=3399997&p=56935277#post56935277

Reply 526

username1385543

reckon i got 68-70 in this exam, but just found out i got 11 in my coursework. what do i need to get in C4 to get an A* and is there anything i can do about my coursework?

Reply 527

Leechayy

Does 70% in the paper and 95% coursework get an A overall?

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Reply 528

Buses

Original post by Harryp642

reckon i got 68-70 in this exam, but just found out i got 11 in my coursework. what do i need to get in C4 to get an A* and is there anything i can do about my coursework?

ouch, is it even possible to get an a* with 11? if so it'll be risky

it is probably going to be 66-ish for an A* on this paper, seeing as how it was easier than last year's

(edited 8 years ago)

Reply 529

OscarH

Original post by Harryp642

reckon i got 68-70 in this exam, but just found out i got 11 in my coursework. what do i need to get in C4 to get an A* and is there anything i can do about my coursework?

I am in exactly the same position as you, but I am in year 12 which does make a difference if you are in year 13.

You need to get 90% UMS in C3 and C4 combined which includes the coursework and comprehension. I think with 81/90 in C3 you will be able to drop about 9 marks in C4 in order to get the 90%.

If you just miss the mark, which is what will most likely happen to me, you can separately re-do the C3 coursework, and hold back your A2 exams for next year. If you are in year 13 then I don't you can affect your grade without doing another year.

Nail C4 and you will be ok

Reply 530

HenryHein

17 in the coursework but from the unofficial mark scheme it looks like I dropped a few marks frequently from silly mistakes: looking at no more than about 58/72 and probably less. Hopefully enough for an A* but an A won't be the end of the world.

Reply 531

OscarH

Original post by Spelly456

For the differentiating implicitly I did the product rule on 2X times lny which gave 2lny + 2x/y Then I multiplied the whole thing by dy/dx as they both have y terms? I now think you only multiply the 2x/y term by dy/dx. Can anyone say whether this is wrong and how many marks I'll lose? My answer came out as 0.5...

That is right.

Reply 532

Leechayy

Original post by HenryHein

I'm in the same boat, RIP pal :colonhash:

Although, 100% in C4 might just do it :tongue:

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Reply 533

OscarH

Original post by Spelly456

Are you sure about the method though? I multiplied dy/dx by both the y terms. 2lny and 2x/y? Thanks.

Unless the examiner can clearly see that you got lucky in getting the right answer, you shouldn't lose marks.

Reply 534

Primus2x

How many marks was question 5?

If I verified it passed through (1,1) how many marks would I get?

If I got the wrong gradient would I still get marks for working out?

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Reply 535

conorw6

Original post by Spelly456

Are you sure about the method though? I multiplied dy/dx by both the y terms. 2lny and 2x/y? Thanks.

You should've only multiplied the 2x/y term by dy/dx but considering you got the right answer I doubt the examiner will notice unless they are looking for a correct expression for dy/dx. They want to mark it quickly so I think if they see a product rule set out with the correct final answer you might get lucky

Reply 536

kevvvvvv

worst c3 paper mei have given

Reply 537

kevvvvvv

no modulus inequalities or equations
no exponential growth or decay questions
no proof questions

Reply 538

username1385543

Original post by Buses

ouch, is it even possible to get an a* with 11? if so it'll be risky

it is probably going to be 66-ish for an A* on this paper, seeing as how it was easier than last year's

so i can drop 6/7 marks in C4? thats not the end of the world, if the paper isnt awful its possible

Reply 539

tuck91

how is the coursework weighted? Is it just a simple matter of adding them together out of 90?

I really ****ed this exam up, reckon I only got about 50/72 max, but got 16 in the course work. Need 215ums for an A this year, so don't mind getting a C in this provided I get an A in C4. So if all the past grade boundaries say 58/90 max is a C, will this mean I got at least a C if I got 42 or above in the paper?