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Advanced Higher Maths 2012-2013 : Discussion and Help Thread

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Original post by -Neuro-
IMAG0344 (2).jpg

For questions 2 and 3 I expanded the whole thing out then found the coefficients. Is this the only method or is there a formula you can use to find the specific term?

I know this is used for two terms: r=0n(nr)xnryr\sum\limits_{r=0}^n \displaystyle \binom{n}{r}x^{n-r}y^r , but is there something for 3 in a bracket?

There's a somewhat quicker way than just trying to expand everything out term by term - real effort :wink:

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(edited 11 years ago)
Original post by -Neuro-
IMAG0344 (2).jpg

For questions 2 and 3 I expanded the whole thing out then found the coefficients. Is this the only method or is there a formula you can use to find the specific term?


Number 2 is 1n5(5n)xn(1+x)n\displaystyle\sum_{1\leq n\leq 5}\binom{5}{n} x^n(1+x)^n

Number 3 is quite simply x3+1+x(x3+1)4x^3+1+x(x^3+1)^4

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Original post by ukdragon37
Yes it's a different cycle.

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Dude, quick question, to apply for a PhD, did you need to take the SAT?
Original post by Felix Felicis
Dude, quick question, to apply for a PhD, did you need to take the SAT?


No, SAT is for applying to undergrad in the US. For graduate programs you take the GRE instead.
Maths is NOT going well for anyone in our class.. (ps hi Joanne if you are creeping as usual) and I'm just reeeeally worried :frown:!

In our mock prelim, our scores were: 6%, 20%ish, 30%ish and 45%.
Really can't see anyone in our class passing! I know there is still plenty of time before the exam, but seriously struggling!

OH WELL, only 8 periods until we finish the course. :dancing2:
Original post by hollieeilloh
Maths is NOT going well for anyone in our class.. (ps hi Joanne if you are creeping as usual) and I'm just reeeeally worried :frown:!

In our mock prelim, our scores were: 6%, 20%ish, 30%ish and 45%.
Really can't see anyone in our class passing! I know there is still plenty of time before the exam, but seriously struggling!

OH WELL, only 8 periods until we finish the course. :dancing2:


Thats the same for my school. I think 3 people passed the prelim out of 18, and 2 of them were low fiftys :tongue: Although we've got far more than 8 periods to finish the course :tongue: We've got our Unit 2 nab on Thursday :tongue: I'll probably try and power through whats left over easter tbh :tongue:
Uh, wow. In my class everyone passed (though there are only 5).
Reply 987
Our class average was 33%, I got more than double that, but I think Reece dominates with 3x it :wink:
My class did quite well in our maths prelim, there were quite a few A's. It's all down to the teacher though, she's absolutely amazing and everyone loves her.

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Original post by Simarilli
Uh, wow. In my class everyone passed (though there are only 5).


Just think everyone here has either lost motivation, or just didn't study :tongue: Hell, the only reason I studied is because I generally enjoy doing Maths. I didn't study much for my other subjects.
Reply 990
There are 16 in my class and most of us passed the prelim. I think maybe 4 failed, and at that not badly, apart from one boy who got 9%. I think there were 4 As, maybe more if I remember correctly? Me being one of course o:-)

I'm really struggling to motivate myself to study now, even though I'm down to three classes. Maths is the only one I'm all right at studying because I actually enjoy doing it, it doesn't seem as onerous as say, memorising essays in Philosophy. I don't mind studying physics either but then I feel guilty because it reminds be that I SHOULD be working on my investigation.
Reply 991
Original post by TheFOMaster
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Original post by ukdragon37
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Original post by Felix Felicis


Original post by Reece:)
This was posted from The Student Room's iPhone/iPad App


Why are we not taught to do it this way.

Given that,
x2eydydx=1\displaystyle x^2e^y \frac{dy}{dx}=1

and y = 0 when x = 1, find y in terms of x.

0yeydy=1xdxx2\displaystyle\int _0^y e^ydy= \int _1^x\frac{dx}{x^2}
And so on.
Is it just me that finds this easier than the general solution method?
(edited 11 years ago)
Original post by I am Ace
Why are we not taught to do it this way.

Given that,
x2eydydx=1x^2e^y \frac{dy}{dx}=1

and y = 0 when x = 1, find y in terms of x.

0yeydy=1xdxx2\int 0_y e^ydy= \int 1_x\frac{dx}{x^2}
And so on.
Is it just me that finds this easier than the general solution method?


Well, I don't know much about the AH system but this one's just a straightforward separable differential equation...do you do integrating factors and the like?
Reply 993
Original post by Felix Felicis
Well, I don't know much about the AH system but this one's just a straightforward separable differential equation...do you do integrating factors and the like?


Look at the edited version,
In the marking instructions for past papers,
we don't use limits, we always use the constant
Original post by I am Ace
Look at the edited version,
In the marking instructions for past papers,
we don't use limits, we always use the constant

Ah, I see. I thought you were just separating the variables first time :P

And you found that in the marking instructions? :s-smilie: Integrating w.r.t. y and having a 'y' in your limit, and the same for 'x' doesn't make sense
Reply 995
Original post by Felix Felicis
Ah, I see. I thought you were just separating the variables first time :P

And you found that in the marking instructions? :s-smilie: Integrating w.r.t. y and having a 'y' in your limit, and the same for 'x' doesn't make sense


I mean using a definite integral instead of indefinite.
For example, how would you solve a separable differential equation?
Would you integrate indefinitely and have a constant, then use initial conditions to evaluate c?
Original post by TheFOMaster
Thats the same for my school. I think 3 people passed the prelim out of 18, and 2 of them were low fiftys :tongue: Although we've got far more than 8 periods to finish the course :tongue: We've got our Unit 2 nab on Thursday :tongue: I'll probably try and power through whats left over easter tbh :tongue:


Aww I'm glad to hear we're not the only ones! :tongue: thought we were all just **** haha! Your plan sounds a lot better than mine - ZERO motivation! We're starting the final outcome tomorrow ( :biggrin: )
Original post by I am Ace
Why are we not taught to do it this way.

Given that,
x2eydydx=1\displaystyle x^2e^y \frac{dy}{dx}=1

and y = 0 when x = 1, find y in terms of x.

0yeydy=1xdxx2\displaystyle\int _0^y e^ydy= \int _1^x\frac{dx}{x^2}
And so on.
Is it just me that finds this easier than the general solution method?


I like it more, it's less messy :smile: I would assume the reason that we aren't taught it that way is because we are taught integration in Higher in the same way. To find the particular solution of an integral, you integrated it and then plugged in values. The general solution method does the same, so we are taught that method since it is exactly the same method as we are taught in Higher.

Original post by hollieeilloh
Aww I'm glad to hear we're not the only ones! :tongue: thought we were all just **** haha! Your plan sounds a lot better than mine - ZERO motivation! We're starting the final outcome tomorrow ( :biggrin: )


I just sat the unit 2 nab :tongue: (Got full marks ^_^) I'll probably end up doing the full of Unit 3 in those two weeks cause of this damn Chemistry investigation... I'll try and get at least the differential equations outcome finished and a start of Matrices or Vectors before Easter :tongue:
Reply 998
Hello.

Struggling a bit with a question:

Screen Shot 2013-03-09 at 19.36.24.png

I get up to where you have to deduce the expressions, and then I'm stuck. The solutions say:

Screen Shot 2013-03-09 at 19.39.13.png

I don't get how you would know to add and subtract the two; am I forgetting a fundamental piece of simple theory?

Thanks.
Reply 999
Original post by Bonzo10
Hello.

Struggling a bit with a question:

Screen Shot 2013-03-09 at 19.36.24.png

I get up to where you have to deduce the expressions, and then I'm stuck. The solutions say:

Screen Shot 2013-03-09 at 19.39.13.png

I don't get how you would know to add and subtract the two; am I forgetting a fundamental piece of simple theory?

Thanks.


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