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AQA Maths Core 3 (Friday 5th June) - Discussion Thread.

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Reply 220

letmepassplz

Here is the c3 june 09 paper....good luck guys!

P.s. rep me :smile:

C3 June 09_0002.jpg506.7KB

C3 June 09_0003.jpg510.9KB

C3 June 09_0004.jpg461.2KB

C3 June 09_0006.jpg362.9KB

C3 June 09_0005.jpg469.6KB

Reply 221

ticktockclock

what did everyone get for the range of f(x), i put y> -2, shoot, i think it should have been y>= -2.

anyone get ln3-4? or something like that. and for the modulus question i put 6<x<-6 and 8<x<-8. would that be right?

i messed up the 2lnx+15/lnx=11 question but it seems a lot of people on here got it right, someone please tell me they got that wrong as well, im hoping they lower the grade boundaries.

Reply 222

LadySmythe

Can someone post some working for the revolutions question please?

I struggled to do this, and this is usually the only question I usually get right :s-smilie:

Reply 223

Jooeee

ticktockclock

what did everyone get for the range of f(x), i put y> -2, shoot, i think it should have been y>= -2.

If you're talking about 2a. Then f(x)>=0 i think

Reply 224

letmepassplz

Jooeee

If you're talking about 2a. Then f(x)>=0 i think

Thats what i wrote! I hope we're right...

Reply 225

meldridge

letmepassplz

Thats what i wrote! I hope we're right...

ditto

Reply 226

thewait

Hold on didn't anyone else get their volumes of revolution as 25pi, thats what i got. Used the limits 0 & 10 and am pretty sure it came out to that. At least thats what whoever i asked at my college got aswell.

Reply 227

Jooeee

Loz17

Can someone post some working for the revolutions question please?

I struggled to do this, and this is usually the only question I usually get right :s-smilie:

Since we're rotating around y-axis we integrate between our limits x^2 with respect to y.

y=\sqrt{100-4x^2}[br][br]y^2=100-4x^2[br][br]4x^2=100-y^2[br][br]x^2=25-\frac{y^2}{4}[br][br]\pi\displaystyle\int^{10}_0 25-\frac{y^2}{4}\ dy [br][br][br]\pi\left[ 25y-\frac{y^3}{12}\right]_0^{10}[br][br]\pi((250-\frac{1000}{12})-0)[br][br]\dfrac{500\pi}{3}

Reply 228

meldridge

Jooeee

Since we're rotating around y-axis we integrate between our limits x^2 with respect to y.

y=\sqrt{100-4x^2}[br][br]y^2=100-4x^2[br][br]4x^2=100-y^2[br][br]x^2=25-\frac{y^2}{4}[br][br]\pi\displaystyle\int^{10}_0 25-\frac{y^2}{4}\ dy [br][br][br]\pi\left[ 25y-\frac{y^3}{12}\right]_0^{10}[br][br]\pi((250-\frac{1000}{12})-0)[br][br]\dfrac{500\pi}{3}

i got 500pi/3

Reply 229

caity

a lot of this is reassuring :smile:

i basically ****** up the integration questions at the end. but i got the solids of rev. differentiating, trig....didn't get the first answer though! bad times!
ahh feeling a bit better though :smile:

thanks guys

Reply 230

ticktockclock

Wevans2303

No that's fine because it is an exact answer in terms of pi.

Probably more complete than either of the other answers. :p:

EDIT: Wait a minute........167 x 12 is 2004 not 2000, don't think your correct???

Actually i got 166.66 recurring so i rounded to 3s.f which is 167.

Reply 231

Jooeee

ticktockclock

Actually i got 166.66 recurring so i rounded to 3s.f which is 167.

I don't think you'd get full marks tbh since it did explicity say exact answer. I'd guess perhaps 1 mark less than the actual amount of marks that were available?

Reply 232

Mr Kipling

I.Hate>Exams

lol. u and me both.
lets just hpe the grade boundaries cum dwn times a million...
well we can hpe ryt? ..... i think this ppr has officially killed me off. "pc3 is easy i sed!" wt on earth possessed me! lols

EXACTLY what I thought....

Reply 233

LadySmythe

Jooeee

Since we're rotating around y-axis we integrate between our limits x^2 with respect to y.

y=\sqrt{100-4x^2}[br][br]y^2=100-4x^2[br][br]4x^2=100-y^2[br][br]x^2=25-\frac{y^2}{4}[br][br]\pi\displaystyle\int^{10}_0 25-\frac{y^2}{4}\ dy [br][br][br]\pi\left[ 25y-\frac{y^3}{12}\right]_0^{10}[br][br][br]\pi((250-\frac{1000}{12})-0)[br][br]\dfrac{500\pi}{3}

Ahh ok, thank you so much.

That questions been annoying me :frown:

Reply 234

ticktockclock

Jooeee

If you're talking about 2a. Then f(x)>=0 i think

oh ****, yeah youre right, what i was thinking of was domain, which they gave you anyway. thats another 2 marks gone, i seriously hope AQA lower the grade boundaries, apparantly it was 57 or 58(cant. remeber which one) for an A, 51 for a B and 43 for a C in the jan09 paper.

Reply 235

ticktockclock

Jooeee

I don't think you'd get full marks tbh since it did explicity say exact answer. I'd guess perhaps 1 mark less than the actual amount of marks that were available?