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

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I would disagree strongly, this seemed like a very average paper to me. The only difficult questions were finding k and the final area question.

Also it's better to assume you have a lower mark than you actually have so you don't get complacent!

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Yes!The two questions you mentioned were the two I struggled with!
Yeah, I'll just forget about C1 now.C2 next!

Reply 521

emiilywest

What happens if you don't simplify fractions, is that marks lost automatically? For instance, on the graph I put the x axis point of intersection as 6/4, not 3/2 :frown:

Reply 522

Charlieukharris

Original post by MacDaddy101

does anyone have an idea on how the 4 marks on the end question about area will be distributed?

I would like to know this too

Reply 523

eajeaj1997

Original post by Renzhi10122

I think the differentiation one was f'(x)=-3x^2+10x-3 and f(x)=-x^3+5x^2-3x+15? Which is f(x)=(5-x)(x^2+3)

Any idea how many marks this was?? :smile:

Reply 524

Rr_rolo

FP1 is cancelled tomorrow

Reply 525

sandpitturtle

Original post by emiilywest

What happens if you don't simplify fractions, is that marks lost automatically? For instance, on the graph I put the x axis point of intersection as 6/4, not 3/2 :frown:

how did you get 6/4 ? i got it as (2x-3) so it had to be 3/2

Reply 526

eddy29

Original post by chloe-jessica

Ah thank you! Completely forgot about that quadratic one, the answers I got were -8 and 27 though so I'll go with these as being right :smile:

Can't remember the differentiation question for the life of me, it was something like f(x)=(x^2+7)(8-x) and you had to find f'(x). I'll edit my post now though, thanks again :smile:

How did you do 9 iii?

Reply 527

Abbie2511

For the 1/x-2 graph transformation, in my head I suddenly decided it was a 1/x^2 graph and put 1/(x-2)^2, is this going to lose me that mark do you think?

Reply 528

eajeaj1997

Original post by Charlieukharris

I would like to know this too

Answer to last part of question 10: You had to put x=0 into the ?circle?(not sure if it was a circle or a curve- can't remember) equation and then solve to find Q, to give you a set of coordinates. Then put x=0 into the straight line tangent equation to find R(can't remember if it was P or R) to find the final set of coordinates for the triangle. I then drew the graph and plotted the 3 points. It was not a right angled triangle on its own. Therefore I then drew a line from (8,2)-one of the points, to the y-axis, splitting the triangle into 2 right angled triangles. Then I just calculated the area of the two triangles separately and added them together to get 40 :smile:

Hope this helps

(edited 8 years ago)

Reply 529

sandpitturtle

someone pls help with how many marks i have lost :smile:

*for the 2nd q i think, i left an answer as 625root5, instead of writing it as 5^k
*for some line one i think that i wrote 6x+8y-29=0 (think) instead of -8y
*for the inequality one, i wrote k as k>25/8 with no minus and sign wrong way round
*and for same question of the graph, for the values of x>0 i wrote answer with signs wrong way round again
*and lastly area of triangle, i wrote 40 then crossed it out and wrote 50, but how many marks for finding Q and R, and writing that area=1/2basexheight ?

thanksss

Reply 530

Exephy

Original post by ella_chloe

how did you get 6/4 ? i got it as (2x-3) so it had to be 3/2

probably just factorised differently, 6/4 is the same as 3/2 but I'm not sure if they'd lose marks for not changing to simplest form?

Reply 531

c223

Original post by eddy29

How did you do 9 iii?

Put your solution for a back into the differential and make this equal to 0. Factorising this gave you, I think, (3x-1)(x+4) = 0 or something similar, so you know the x coordinate of the other TP is going to be 1/3.

less than -25/8

Original post by ella_chloe

someone pls help with how many marks i have lost :smile:

1) Possibly 1 out of 2 for the second question.
2) Provided your method was right for the line question and it was just a stupid mistake copying down, you should only lose the 1 accuracy mark.
3) Did you find the discriminant of the equation and make it less than 0? This would be worth method marks.
4) You might get 1 out of 2. If you drew your graph wrong it might be counted as ecf.
5) Should only be the 1 lost mark for accuracy again.

Not 100% sure on these but that's what I'd guess at.

Reply 534

sandpitturtle

Original post by Exephy

probably just factorised differently, 6/4 is the same as 3/2 but I'm not sure if they'd lose marks for not changing to simplest form?

yeahh i know but was just confused, they should still give you the marks yeah :smile:

Reply 535

Cyphi3R

Original post by qwerty1357

less than -25/8

Phew, I got the same :biggrin:

Reply 536

Renzhi10122

Original post by eajeaj1997

Any idea how many marks this was?? :smile:

No sorry, but I don't think it's more than 3 for that part

Reply 537

GM16

Original post by Madhutty

The question about the stretch of -1/x

The answer is as follows:

Stretch
Scale factor 1/3
In EITHER direction

THIS GRAPH (http://puu.sh/hLU2t/a0228020ae.png) shows the pre-stretch graph, and the post-stretch graph.

So you must state it was a stretch in both the x and y directions? Or will you still get the marks if you say x or y?

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Reply 538

sandpitturtle

Original post by chloe-jessica

thank you, for 2 yes i think right method y-y1=m(x-x1), and for 2 i did yh b^2-4ac<0 but always mess up inequality signs, and 4 i believe that i drew the graph right but just wrote inequality sign wrong way round, i thought for last i'd lose like 3 marks, but i am always pessimistic when it comes to marks lost aha
thanks :smile:

Reply 539

c223

Original post by GM16