OCR Core 4 (not mei) How did it go?

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Reply 60

ChanandlerBong

Buggar. Ah well.

Reply 61

Mustard-man

john-boro

you will notice that 1/288 x 1/2 is 1/576

so maybe you'll lose a mark for not simplifying, but maybe not even that.

:smile:

I got something with 1/288, where on earth did the 1/2 come from?

Reply 62

boyonthehill

Bloody good exam for me, I just marked what I did. I didnt quite get 5 ii) and I got 1/288 instead of 1/144 on Q.8 (just did it agen and got it right :frown:

) . I think i got about 65/72 :smile:

Im really happy with it

Reply 63

ChanandlerBong

Mustard-man

I got something with 1/288, where on earth did the 1/2 come from?

Because most people got something with 1/576, he was just noting that 1/288 x 1/2 = 1/576

Reply 64

john-boro

Mustard-man

I got something with 1/288, where on earth did the 1/2 come from?

I can't remember to be honest, but I'm pretty certain about it and so are quite a few others.

Reply 65

boyonthehill

Mustard-man

I got something with 1/288, where on earth did the 1/2 come from?

It was (pie^2 / 288) - (pie^2 / 576) - (1/288) - (1/288)

= (pie^2/576) - (1/144)

Reply 66

john-boro

Gamma

Any estimates on grade boundaries, people?

Well usually its 58 for an A, and to be honest I think this is the kind of paper that the majority of people will find hard. Certainly that was the common opinon at my school, so if anything the grade boundaries might be lowered - only by a mark or so though.

Reply 67

Chewwy

haha, you can't spell pi.

Reply 68

john-boro

chewwy

haha, you can't spell pi.

no, you can't spell pie!!!

Reply 69

Head

1. gradient = -2

2. i) 1 + 6x +27x^2

ii) coefficient of x^2 = 55

3. i) 1/x - 1/(3-x)

ii) crosses x axis so area above the x-axis being is the same as the area below the x-axis.

4. i) angle between the lines = 45.3 deg

ii) area = 3.54 units^2

5. i) dA/dt = kA^2

ii) 2 and 1/3 hours

7. i) lamda = -2

the u thing = 3

so a cannot equal 2

ii) intersect at (-5, -4, 0)

8. integral of xcos^2 x between 0 and pi/12 = 1/576(pi^2 - 4) *this is right i checked it on my calculator*

9. i) dy/dx = -3cost/4sint

iv) min value of area = 12 when p =pi/4

thats all apart from the show thats.

just thought i'd re-post this to bring it forward. i think we're all in agreement these are right? if so i got 66/72 plus any method marks for the one i got wrong. Boss.

Reply 70

mcooper

yes I agree with all those answers.

I thought the paper was slightly more difficult than the C4 paper from January 2006 but still perfectly acceptable and quite a nice paper to work through.

Merlin

Reply 71

Head

i thought it was easier but i only spend about half an hour on past papers and i tend to do better in the real thing.

Reply 72

mcooper

yes there were 2 questions on vectors in this paper which is not the norm really (especially when each question is worth 8 marks).

Good differential equation whereby the constant of integration has to be found in terms of K and then subsequently find K from the second piece of information given.

Apart from a silly mistake in the first one whereby for some reason I put that -2x2 =8 I think it went very well.

Reply 73

mcooper

not sure your working seems ok so I guess the number crunching didn't go to plan.

Reply 74

mcooper

not sure your working seems ok so I guess the number crunching didn't go to plan.

Reply 75

Head

dunno but when i did

a.b. = |a| |b| cos x

it came out as

7 = (root 11)(root 9)cosx

7 / (3root11) = cos x

Reply 76

mcooper

My working was exactly the same as that above.

by the way sorry about the duplicate posts for some reason the repsose from the website goes dead quite often and therefore multiple posts go through.

Reply 77

Head

i always get confused with the directional vectors of lines whether they should be + or - each part but i worked out that it didnt make a difference on this question so i was ok.

Reply 78

Lucyvet2006

Yay- thanks for posting up the paper! I did a quick post-mortem and think I got about 50/72, approximating the marks they give for working. Hoping that's a B- would be nice to get a UMS mark above 70 but judging as it wasn't a mean paper I doubt the marks will get rounded up very much!