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Year 13 Maths Help Thread

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@AMarques

Original post by RDKGames
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Original post by Math12345
Differentiate it twice and sub it into the differential equation.


Differentiate what? y=Ay1+By2y=Ay_1+By_2?
Original post by RDKGames


Plug it into the DE and note that you get (constants)[de with only y1 and y2] so the square bracket is 0, making the entire thing 0.
Original post by RDKGames
Differentiate what? y=Ay1+By2y=Ay_1+By_2?


Yh.
Original post by RDKGames
Differentiate what? y=Ay1+By2y=Ay_1+By_2?


Yep you know y=y_1 and y_2 are solutions so y=ay1+by2 is a solution iff when plugged in it is zero. Diff and factor out and collect terms you get A(0)+B(0)=0



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Original post by RDKGames
Differentiate what? y=Ay1+By2y=Ay_1+By_2?


Yes. y′=Ay1′+By2′⇒y′′=Ay1′′+By2′′y' = Ay_1' + By_2' \Rightarrow y'' = A y_1'' + By_2''

Plug into the DE: aAy1′′+aBy2′′+bAy1′+bBy2′′+cAy1+cBy2aAy_1'' + aBy_2'' + bAy_1' + bBy_2'' + cAy_1 + cBy_2 now work with this knowing that ay1′′+by1′′+cy1=0ay_1'' + by_1'' + cy_1 = 0 and same for y_2.
Original post by RDKGames
Im not sure where to begin with this question as I don't understand what they're asking for, any hints? Q7

ImageUploadedByStudent Room1471377594.129841.jpg


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If y1=g(x) y_1 = g(x) and y2=h(x) y_2=h(x) , then we have y=Ag(x)+Bh(x) y=Ag(x)+Bh(x) . Subbing his into the ODE gives ad2dx2(Ag(x)+Bh(x))+bddx(Ag(x)+Bh(x))+c(Ag(x)+Bh(x)) a\frac{d^2}{dx^2} (Ag(x)+Bh(x)) + b\frac{d}{dx} (Ag(x)+Bh(x)) +c(Ag(x)+Bh(x)) . Using the fact that differentiating is a linear operation, you can essentially split it into two separate differential equations and obviously they sum to 0 as they are both equal to 0.
Original post by Math12345
Yh.


Original post by physicsmaths
Yep you know y=y_1 and y_2 are solutions so y=ay1+by2 is a solution iff when plugged in it is zero. Diff and factor out and collect terms you get A(0)+B(0)=0

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Original post by Zacken
Yes. y′=Ay1′+By2′⇒y′′=Ay1′′+By2′′y' = Ay_1' + By_2' \Rightarrow y'' = A y_1'' + By_2''

Plug into the DE: aAy1′′+aBy2′′+bAy1′+bBy2′′+cAy1+cBy2aAy_1'' + aBy_2'' + bAy_1' + bBy_2'' + cAy_1 + cBy_2 now work with this knowing that ay1′′+by1′′+cy1=0ay_1'' + by_1'' + cy_1 = 0 and same for y_2.


Ah yes, I've done it and factored out the A's and B's. Got left with differentials of y1y_1 and y2y_2 in both brackets respectively. Since y1y_1 and y2y_2 are solutions then the DE's in both brackets equal 0 thus making the whole thing equal 0 which is to be expected. I get it, thanks. Didn't quite understand the wording of the question.
Guys ive just opened my results - i got an A in AS Maths!! I did not expect that and am so happy right now :smile:

Firstly, i just wanna say thanks to all the people who helped me last year. Especially, @Zacken for answering nearly all my questions!! (Even the random/easy ones) :biggrin:

Now i just need to master the A2 content :smile:

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(edited 7 years ago)
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What is the number of unique arrangements of AAXABBCC with the condition that at least one A has to go after the X and at least one A has to go before the X? (I have already solved this myself but I want to know if somebody can do it more efficiently than I did).
Original post by kiiten
Especially, @Zacken for answering nearly all my questions!! (Even the random/easy ones) :biggrin:


Very well done to you! Thanks for the special mention. Good luck for you A2's. :smile:
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Original post by kiiten
Guys ive just opened my results - i got an A in AS Maths!! I did not expect that and am so happy right now :smile:

Firstly, i just wanna say thanks to all the people who helped me last year. Especially, @Zacken for answering nearly all my questions!! (Even the random/easy ones) :biggrin:

Now i just need to master the A2 content :smile:

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Congratulations on your results and it's good to hear that this thread has been of much use to you, with credit due to the helpers (especially Zacken) for making this project work!
Reply 392
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I also got my AS Maths and Further Maths results and I got my A grades (which I am very relieved about). I owe a lot of credit to this thread for carrying me through the year (special mention to Zacken for putting up with my silly C3/C4 inquiries!).

I've decided against mechanics in favor of statistics as the latter is easier.
Got a B (3 UMS off an A) in AS Maths, a bit disappointed but it reflects the effort I put in.. definitely going to try a lot harder this year. Can anyone please recommend me any resources for Core 3 & Core 4? Also, I may resit Core 2 next year - does it become a lot easier after doing Core 3 & Core 4? I really need an A in Maths, going to apply for Physics degrees.

Thanks!
Reply 394
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Original post by DarkEnergy
Got a B (3 UMS off an A) in AS Maths, a bit disappointed but it reflects the effort I put in.. definitely going to try a lot harder this year. Can anyone please recommend me any resources for Core 3 & Core 4? Also, I may resit Core 2 next year - does it become a lot easier after doing Core 3 & Core 4? I really need an A in Maths, going to apply for Physics degrees.

Thanks!


Resources...

This thread can be great for queries about questions if you don't want to create a new thread each time.
DrFrostMaths has some amazing slides for C3/C4 maths.
This has loads of papers from 1988-2014 http://mathematics-solutions.co.uk/edexcel-directory/
http://madasmaths.com/ has 'Special Papers' where you can stretch yourself on your grasp of C1/C4

Of course there's also ExamSolutions (videos with worked examples which I found helpful in FP1)
(edited 7 years ago)
Original post by DarkEnergy
Got a B (3 UMS off an A) in AS Maths, a bit disappointed but it reflects the effort I put in.. definitely going to try a lot harder this year. Can anyone please recommend me any resources for Core 3 & Core 4? Also, I may resit Core 2 next year - does it become a lot easier after doing Core 3 & Core 4? I really need an A in Maths, going to apply for Physics degrees.

Thanks!


In a way it's promising if you didn't put much effort in and came that close - hopefully you can be predicted an A.

If you're with Edexcel then the textbooks are pretty much all you need - after that's done, seek out extension material eg solomon papers. If you're stuck and need guidance, try examsolutions.

I sat C2 again and after C3 and C4 people do find it a lot easier. Though one person I know rather worryingly got a trig question partially incorrect as they cancelled out some functions instead of factorising.. rather worrying as it features a lot in C3, and is difficult at first but just takes practice) but I digress :lol:

Just practice, practice, practice and you should be fine.
Original post by Palette
I also got my AS Maths and Further Maths results and I got my A grades (which I am very relieved about). I owe a lot of credit to this thread for carrying me through the year (special mention to Zacken for putting up with my silly C3/C4 inquiries!).

I've decided against mechanics in favor of statistics as the latter is easier.


Original post by DarkEnergy
Got a B (3 UMS off an A) in AS Maths, a bit disappointed but it reflects the effort I put in.. definitely going to try a lot harder this year. Can anyone please recommend me any resources for Core 3 & Core 4? Also, I may resit Core 2 next year - does it become a lot easier after doing Core 3 & Core 4? I really need an A in Maths, going to apply for Physics degrees.

Thanks!


Well done. Now the real fun of A-Levels start. No pressure, it will only determine what uni you go to. :tongue:

In response to DarkEnergy, C2 definitely becomes much easier after C3 and C4 as they build up on the content of C2. Though some stuff like the arc length with radians you might want to keep handy as it doesn't appear very often across C3/C4. Both C3 and C4 can easily be done using the exam board's textbooks, no extra material needed. Though you can look on different websites for more challenging questions I suppose.
Original post by Palette
(..)


Thanks!

Original post by SeanFM
In a way it's promising if you didn't put much effort in and came that close - hopefully you can be predicted an A.

If you're with Edexcel then the textbooks are pretty much all you need - after that's done, seek out extension material eg solomon papers. If you're stuck and need guidance, try examsolutions.

I sat C2 again and after C3 and C4 people do find it a lot easier. Though one person I know rather worryingly got a trig question partially incorrect as they cancelled out some functions instead of factorising.. rather worrying as it features a lot in C3, and is difficult at first but just takes practice) but I digress :lol:

Just practice, practice, practice and you should be fine.


Thank you for the response.. I suppose I got lucky, could've been a lot worse but I was at least expecting an A in Core 1. It was only 53/72 for an A and when I added up marks from unofficial mark schemes I definitely got higher than that, so might go for a remark.

If I were to resit C2, but ended up doing worse, do they have to use the 'latest' mark or is it just the better of the two?

Original post by RDKGames
In response to DarkEnergy, C2 definitely becomes much easier after C3 and C4 as they build up on the content of C2. Though some stuff like the arc length with radians you might want to keep handy as it doesn't appear very often across C3/C4. Both C3 and C4 can easily be done using the exam board's textbooks, no extra material needed. Though you can look on different websites for more challenging questions I suppose.
Thanks
(edited 7 years ago)
Original post by DarkEnergy
Thanks!



Thank you for the response.. I suppose I got lucky, could've been a lot worse but I was at least expecting an A in Core 1. It was only 53/72 for an A and when I added up marks from unofficial mark schemes I definitely got higher than that, so might go for a remark.

If I were to resit C2, but ended up doing worse, do they have to use the 'latest' mark or is it just the better of the two?

Thanks


Better of the two.
Original post by kiiten
Guys ive just opened my results - i got an A in AS Maths!! I did not expect that and am so happy right now :smile:

Firstly, i just wanna say thanks to all the people who helped me last year. Especially, @Zacken for answering nearly all my questions!! (Even the random/easy ones) :biggrin:

Now i just need to master the A2 content :smile:

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Congratulations! Don't worry, A2's will be a breeze if you keep it up. :congrats:

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