AQA A2 MFP3 Further Pure 3 – 18th May 2016 [Exam Discussion Thread]

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Reply 300

Emi1998

anyone avaliable to help/showquickly what they did for 8aii on Jan 13 please??

Reply 301

XxswagmasterxX

Original post by IrrationalRoot

Certainly 14/15 if you haven't done them but otherwise Jan 13 looks nice. Older ones maybe Jan 07? Plus June 09, Jan 10 (lol I don't expect you to try all of these btw) since there's a cheeky 11 marker thrown in there :biggrin:

Dont forget those 2004 2005 polar qs

Reply 302

XxswagmasterxX

Original post by Emi1998

anyone avaliable to help/showquickly what they did for 8aii on Jan 13 please??

EZ finding are between pi/2 and pi/3

Reply 303

B_9710

Original post by Emi1998

anyone avaliable to help/showquickly what they did for 8aii on Jan 13 please??

If you get the integral into the from

\displaystyle \int \left (1-\cos 4\theta +2\sin^2 \theta \cos^3 \theta \right ) d\theta

, you can make the sub

u=\sin \theta

or you can split the RHS of the integral (integrate the 1+cos 4 theta on the LHS on it's own) to make it look like this

Unparseable latex formula:

\sin^2 \theta \cos^2 \theta \cos \theta = \sin^2 \thtea (1-\sin^2 \theta )\cos \theta =\sin^2 \theta \cos \theta -\sin^4 \theta \cos \theta

.
Using the result from the earlier part of the question now.
I think people who have knowledge of reduction formula's have an advantage as you split the integral up in a similar way as you would when finding a reduction formula.

(edited 7 years ago)

Reply 304

2014_GCSE

On 8bii) of June 2015, I don't understand why you ignore the other two roots of the equation? I don't understand the mark-schemes reasoning.

(edited 7 years ago)

Reply 305

Zacken

Original post by 2014_GCSE

On 8bii) of June 2015, I don't understand why you ignore the other two roots of the equation?

Am I looking at the right paper? There doesn't seem to be a Q8, perchance is it a question about length in which case you ignore the negative roots because a length is a positive quantity?

Reply 306

XxswagmasterxX

May the odds be ever in your favor

Reply 307

2014_GCSE

Original post by Zacken

Am I looking at the right paper? There doesn't seem to be a Q8, perchance is it a question about length in which case you ignore the negative roots because a length is a positive quantity?

Sorry I meant 7 b ii) and ah yes, that makes sense for Rb, but why do they ignore R = 1.5?

Wait, never mind, I get it!!

Reply 308

Zacken

Original post by 2014_GCSE

Sorry I meant 7 b ii) and ah yes, that makes sense for Rb, but why do they ignore R = 1.5?

Wait, never mind, I get it!!

Awesome.

Good sleep = OP

Hope you all achieve what you need and more! :goodluck:

Reply 311

2014_GCSE

In my maths book it says there can be an exceptional case in the paper where if you had no "y"s in the differential equation, then you increase the power on the particular integral and then keep going down.
What I mean by this is if you had say:

f''(x) + f'(x) = 2, instead of f''(x) + f'(x) + y = 2

The P.I would be "y = ax + b" instead of "y = a".

Can anyone shed any light on this? Not seen this in any past papers...

Reply 312

Argylesocksrox

Original post by 2014_GCSE

I always use an order 1 above that of your expected PI if it's a non standard D.E.

Reply 313

Argylesocksrox

Having only 3 hours sleep makes me a bit anxious for an hour and a half of differential equations/polars...

Reply 314

2014_GCSE

Original post by Argylesocksrox

I always use an order 1 above that of your expected PI if it's a non standard D.E.

Okay, thanks! Could you state what kind of thing would exactly be regarded as a "non standard D.E"?

Original post by Argylesocksrox

Having only 3 hours sleep makes me a bit anxious for an hour and a half of differential equations/polars...

Yep, I know how you feel. I only got 4 and half so slightly better but still not great. :frown:

Reply 315

Argylesocksrox

Original post by 2014_GCSE

Okay, thanks! Could you state what kind of thing would exactly be regarded as a "non standard D.E"?

Yep, I know how you feel. I only got 4 and half so slightly better but still not great. :frown:

Well, in specific cases there's y''=f(x) in which you can simply integrate both sides twice, then there's y''+y'=f(x) in which a substitution works, ie p=dy/dx hence dp/dx=d^2y/dx^2 etc,

then y''+y=f(x) which is pretty easy, these are the only real non standard D.E's.