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OCR Core 1 Mathematics

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Reply 120

Glutamic Acid

I can't remember my answers for the simultaneous one, but I think they factorized.

Reply 121

.Adrian.

patel cautious wooo hehe

that the one im nervous of losing mark on. so ive only lost 1 mark i think

and the simultaneous ones you had to use quadratic formula or factorise but i used formula and it came down to a nice number and fraction in the end :smile:

Reply 122

fishandchips

deathrow

what was the answer to the simultaneous equation?
i got something like
4x^2 - 18x + 21 or something
the thing doesnt factorise and when i used the quadratic equation it came out with bull **** fractions, just like every other question
why cant they just have on question that just uses whole numbers

The equation was x+2y=4 wasn't it?
Did you make x the subject so it was like x=4-2y or something? For that question I did that at first and it wasn't factorising so I left it, came back to it later and instead did it the other way around (so i multiplied the other equation by 2 so i could equate 4-x for it). And it ended up factorising. Might have been a mistake though, I didn't have time to check.

Reply 123

ChrisKing

deathrow

I got to that also! although instead of x i used y and got
4y^2 - 18y + 21...

I let this equal y, so y = 4y^2 - 18y + 21

Then took y away from both sides to get 0 = 4y^2 - 19y + 21
This then factorised to get 2 y-values, putting them back into the second equation (x+2y=4 was it?) I then got my x values, both seem to work in the quadratic equation too :smile:

Can anyone confirm is this is the right way to answer the question or not?

Reply 124

fishandchips

Glutamic Acid

8 (iii) For what values of x does x^3 - x^2 - x + 3 decrease as x increases.
I solved dy/dx < 0.

Oo dammit, the wording confused me so much.

Reply 125

.Adrian.

kingy yes your right you can factorise it but i used formula for the safe side as i had a lot of time to spare.

but damn i left the second answer as 14/8 forgot to simplify it. they would mark me down for tht? or is that way to harsh as they didnt tell me to do it in the question??

Reply 126

i'm no superman

For that one I got -1 <= x <= 1/3.

Drawing a sketch of the curve helped a lot.

Reply 127

ChrisKing

I used the formula too Adrian, better safe than sorry I suppose!

Reply 128

.Adrian.

65 marks to get over 90%. i think ive managed it :smile:

yer kingy and mena i drew the curve as well but differentiating it was clever thining under pressure glutamic.

Reply 129

deathrow

Kingy-13

Can anyone confirm is this is the right way to answer the question or not?

Yeah i meant Y, i'm so used to using x's!
and thats right. I set it to 0 straight away, for got to minus the Y.
I was thinking while i was doing it, 19 factorises but 18 doesn't. I should get a few method marks at least

Reply 130

Glutamic Acid

.Adrian.

It think you'll get away with it, there's only 4 marks for the question so I doubt they'll worry too much about cancelling.

Reply 131

Glutamic Acid

.Adrian.

65 marks to get over 90%. i think ive managed it :smile:

yer kingy and mena i drew the curve as well but differentiating it was clever thining under pressure glutamic.

It may not necessarily be 65 raw marks, it depends on the difficult of the paper. It could be higher or lower.

Reply 132

.Adrian.

yer true but im using basic guidline from past yer until i know :smile:

Reply 133

TC88

Hmm, what was the raw mark for an A for last years papers?

for the 2root x >>> 3 root x question... i put stretch in scale factor 3/2 parallel to y-axis.. instead of 1.5 :s-smilie:

i doesnt matter right? as their the same ...

Reply 134

Glutamic Acid

^ It won't matter at all.

Reply 135

TC88

Glutamic Acid

^ It won't matter at all.

Thanks for confirming :cool:

Reply 136

i'm no superman

I'm fairly certain the grade boundaries will be much lower. Those random figures and odd answers we all got and confirmed took a bit of thinking and logic which might have overwhelmed a lot of candidates. Looking back at Jan 07's paper, I think it's fair to say we had a tough ride this year compared to last but our answers have matched and the paper was harder for a lot of people so it's really in our favour.

I wouldn't put the minimum requirement for an A past 62/72 though.

Reply 137

3107a

Hi all, first of all i'd like to thank all of you!! Your answers seem like mine :smile:

. I swear that test was so hard compared to some of the past papers :frown:

I do know i've got some wrong :frown:

. But i definitely feel a bit more confident.

Good luck all for your future tests and results

Reply 138

lethal1

I knew I should not have open this thread....

You all got me Shi*ting it to bits now!

why! why I ask you all!

I always say to my self that you should never regret what you have done! but I am kicking myself now..

Some of these answers said on this post do not make sense at all!.. and that scares the living life out of me!