OCR A Maths C1 & C2. How did it go?

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In that question with the sum of first 100, there was a pattern forming when you added up the terms from the first part. As the total I think I got 1.

Oh gosh, for that question with the perimeter(no 7 i think) i could not find the length of DC. I'm sure it wasn't tricky but I couldn't see anything. Anyone did that? I found arc length so I guess I'll get 1 mark from there. :confused:

Reply 21

Giggsy11

so is it ok to sketch the graphs in the booklet then?

Reply 22

ironically

For 8 i)

I'm not sure what the figures were so bare with me...

firstly V = 8 = x^2y (where y is the hight of it)
rearrange...

y = 8/x^2

Then area of surface = 2x^2 (the bases) + 4xy (the other four faces)

Substitute:

= 2x^2 + 4x(8/X^2)
=2x^2 + 36/x

if that makes sense to anyone who was wondering?

Reply 23

m00c0w06

The geometric question about the money in the bank was a bit wierd. What answer did everyone get?

I got £124000 (3 SF) for the total amount saved on the last part.

Oh gosh, for that question with the perimeter(no 7 i think) i could not find the length of DC. I'm sure it wasn't tricky but I couldn't see anything. Anyone did that? I found arc length so I guess I'll get 1 mark from there.

You just had to use the cosine rule on the angle of 1.7 rads and the two sides which were the radii for that bit.

Reply 24

jason01

But everything after that was piss easy!

You should get at least 90% than.

Reply 25

jason01

Why is it to the power of 2 y

Reply 26

fivestarrambler

i have done so bad. on c1. what do ppl think?? i got a D in jan, so if i did relatively ok on c2 i will get a c?? and then d1...may just pull me up 2 a B...which is what i need....someone please reasure me!!!! xx

Reply 27

Giggsy11

please can someone tell me if it was OK to sketch the graphs in the booklet or not?

Reply 28

fivestarrambler

yes im sure it was :smile:

Reply 29

zulutom

hey, did any1 manage to solve sinx = -cosz for 0<x<180 (Q5 or 6 i think) on C2, i did the one above it ok but that just went wrong...i tried using tanx=sinx/cosx....is this wrong.....any1???

Reply 30

saqibhs

Matt1989

I was unsure about that too. I thought that was a bit too easy for a 3 mark question so i used da fourmula by summing up consecutive terms and the difference was zero and I got 50 aswell!

But everything after that was piss easy! :biggrin:

The geometric question about the money in the bank was a bit wierd. What answer did everyone get?

all you had to do is to do the sum of first 100 terms first and then sum to first 50 terms and then take one away from other.

c2 was a fair paper i thought.

Reply 31

zulutom

hey, did any1 manage to solve sinx = -cosx for 0<x<180 (Q5 or 6 i think) on C2, i did the one above it ok but that just went wrong...i tried using tanx=sinx/cosx....is this wrong.....any1???

Reply 32

Matt1989

Can anyone remember the remainder thereom questions polynomial?

I think it was, 2x^3 + 5x^2 - 7x - 10 = 0?
The when I diveded it by (x+2) i got (2x^2 + x - 9) and so the remainder was -18.

I got 4.5 units squared for the integration question.

I got 1.09 for the trapezium question.

This is how I did the log question:

x log10 (1/2) = log10 (1/6)

x log10 1 - x log10 2 = log10 1 - log10 6

x log10 2 = log10 6

x log10 2 = log10 2 + log10 3

x = (log10 2 / log10 2) + (log10 3 / log10 2)

x = 1 + (log10 3 / log10 2)

Reply 33

saqibhs

zulutom

hey, did any1 manage to solve sinx = -cosx for 0<x<180 (Q5 or 6 i think) on C2, i did the one above it ok but that just went wrong...i tried using tanx=sinx/cosx....is this wrong.....any1???

yh thts the only one i couldnt do there is always something which through you out.

Reply 34

Elondra

m00c0w06

I got £124000 (3 SF) for the total amount saved on the last part.

You just had to use the cosine rule on the angle of 1.7 rads and the two sides which were the radii for that bit.

Omg omg it was right infront of me and I couldn't see it. :mad:

I got angles and the sine rule involved for some reason :confused:

Oh well that's only 3 marks lost. Damn I lost a bet though!

Reply 35

agonline

Yep, you had to use tan.

I thought it was quite tricky myself, and had a royal mare on the quotients question for some reason; I think I missed out a one somewhere, and ended up 0.5 too low for the answers in part a, and therefore got the answers to the next part completely wrong as well.

I'm kicking myself now; does anyone know if they carry errors forward? (ie will they bother working out the second part answers with the answers that I got for part a?).

:confused:

Reply 36

Matt1989

zulutom

hey, did any1 manage to solve sinx = -cosx for 0<x<180 (Q5 or 6 i think) on C2, i did the one above it ok but that just went wrong...i tried using tanx=sinx/cosx....is this wrong.....any1???

yeh i think it was:

sin(2x) = -cos(2x)

Then divide both sides by cos(2x):

tan (2x) = -1

Then solve. I can't remember the exact question though...

Reply 37

Mustard-man

ironically

Dammit that looks correct, why the hell didn't I go on further?!?!?!
I'll probably get a mark for y = 8/x^2

Reply 38

Head

i was retaking c1 since i first took it in jan05, i thought it was a piece of piss after doin c3 and c4 and i'd be surprised if i havent got 100%, especially if everyone else thought it was hard then the UMS might get scaled up even if i did make a mistake.