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Higher Level Maths 2009(Paper 1): How was it for you?

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  • Closed Accounts Posts: 5,109 ✭✭✭QueenOfLeon


    Sweet wrote: »
    For 2(c) I got q>-36/5. Anyone able to confirm this?!

    That rings a bell. Except mine involved a square root and an R somewhere..:o
    kevogy wrote: »
    was question 3 b ii) (-1 0 ) diagonal matrix?
    (0 -1 )


    -1^17 ?

    I got that. That was A^3, so i put it to the power of 5 to get A^15, then multiplied it by A^2 to get A^17. Dont even know if thats allowed!
    Davidius wrote: »
    I just realised that I never sketched the curve.

    Le bollox.

    Ah god, sorry, just realised i probably reminded people if they forgot it. Don't worry about it, if it helps i got mad at mine and it looked a bit wrong :p


  • Registered Users Posts: 2,604 ✭✭✭xOxSinéadxOx


    was 1. (c) REALLY REALLY easy for a (c) part or did I just do it wrong?


  • Moderators, Society & Culture Moderators Posts: 12,524 Mod ✭✭✭✭Amirani


    Did anyone else get 2 C(ii) in terms of r, and then state that q is greater than or equal to the coeffiecent as r is positive? Sound in any way right?


  • Registered Users Posts: 131 ✭✭Nihilist21


    kevogy wrote: »
    was question 3 b ii) (-1 0 ) diagonal matrix?
    (0 -1 )


    -1^17 ?

    That was the matrix I got, pretty sure it's right. However to raise it to the power of 17, it would have been A^3 5 times which was the diagonal matrix, then multiply by A^2.


  • Closed Accounts Posts: 189 ✭✭kevogy


    i added up what i thought i got right and put over 600

    160
    ---- multiply by 100
    600

    around 26 %

    is this 26% of the entire maths exam?


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  • Registered Users Posts: 1,595 ✭✭✭MathsManiac


    r = (5*q^2)/36.

    So, for r to be a positive integer, q has to be a multiple of 6. q={6, 12, 18, ...}


  • Moderators, Society & Culture Moderators Posts: 12,524 Mod ✭✭✭✭Amirani


    Sweet wrote: »
    For 2(c) I got q>-36/5. Anyone able to confirm this?!

    Question said that q was positive. I got the square root of 36/5 * r.


  • Closed Accounts Posts: 160 ✭✭.:FuZion:.


    Not a bad paper.

    1(C): C = B + 1???
    2(C): I got r = q(p^2)n or something. Dont think its right. And q = (+-) 6?


  • Registered Users Posts: 28 Toad-Girl


    was 1. (c) REALLY REALLY easy for a (c) part or did I just do it wrong?


    Ya I thought so too...It was much easier then the first two parts which didn't make much sense...

    Am I the only one who thinks it was an unnecessarily difficult paper?? integration in question 3, awkward algebra, grrr matrices (so disappointed with that..) and no proof of negative de moivre or factor!! I'm terrified I've failed it now to be honest. Please tell me someone else found it difficult!!


  • Closed Accounts Posts: 407 ✭✭OxfordComma


    Just as a matter of interest, what answers did ye get for 1(c)?

    I got c=b+1

    ... and then I realised that the square root of b^2 could be -b as well...

    so my answer was c=+/-b+1


    Am I way off???


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  • Registered Users Posts: 1,595 ✭✭✭MathsManiac


    7(c)

    (ii) f(2)<0 and f(2.5)>0, so root is between 2 and 2.5. QED.

    (iii) One go each at N-R: Ann gets 2.66 and Barry gets 2.58. Since we know the root is less than 2.5, Barry is now closer than Ann.


  • Registered Users Posts: 2,604 ✭✭✭xOxSinéadxOx


    Toad-Girl wrote: »
    Ya I thought so too...It was much easier then the first two parts which didn't make much sense...

    Am I the only one who thinks it was an unnecessarily difficult paper?? integration in question 3, awkward algebra, grrr matrices (so disappointed with that..) and no proof of negative de moivre or factor!! I'm terrified I've failed it now to be honest. Please tell me someone else found it difficult!!

    I did find it quite difficult. just thought it was a nice paper if I had studied like, it was definitely fair I was just underprepared.




    how do you differentiate sin(3x^2 + x) or whatever it was
    it was an (a) part


  • Registered Users Posts: 11,440 ✭✭✭✭Piste


    I thought it was an ok paper. I'm not counting maths for points though, but it's be nice to get a B.

    For a lot of the C parts in algebra I just dicked around with the numbers, multiplied them by stuff, backwardsed them, turned them topwise and just chucked down whatever answer I got.

    Very happy tho ol' cone came up, and I didn't forget my +Cs :D

    I think my differentiation Qs were a bit dodgy, I thought the c part of 7 was a bit weird but I think I worked it out.

    Sequences and series was alright, but I messed up the C part (ii) so therefore messed up the (iii) part.

    I just know I made a load of little mistakes like getting signs wrong and writing the wrong number and stuff. Might possibly still be able to get a low B.


  • Moderators, Society & Culture Moderators Posts: 12,524 Mod ✭✭✭✭Amirani


    how do you differentiate sin(3x^2 + x) or whatever it was it was an (a) part

    Chain rule...


  • Registered Users Posts: 1,082 ✭✭✭Fringe


    I got that. That was A^3, so i put it to the power of 5 to get A^15, then multiplied it by A^2 to get A^17. Dont even know if thats allowed!

    I just said (A^3)^17/3. -1^(-17/3) is -1. It ends up being the same though.


  • Registered Users Posts: 528 ✭✭✭ayapatrick


    i spose the damage is done at this stage, no point worryin about it guys!:D


  • Closed Accounts Posts: 407 ✭✭OxfordComma


    I did find it quite difficult. just thought it was a nice paper if I had studied like, it was definitely fair I was just underprepared.




    how do you differentiate sin(3x^2 + x) or whatever it was
    it was an (a) part

    You differentiate the sin part and the angle separately...

    So you get cos(3x^2+x) and then differentiate what's inside the brackets. So it's cos(3x^2+x)(6x+1)


  • Registered Users Posts: 2,604 ✭✭✭xOxSinéadxOx


    Chain rule...

    yeah but how I think I did it wrong :(


  • Closed Accounts Posts: 189 ✭✭kevogy


    how do you differentiate sin(3x^2 + x) or whatever it was
    it was an (a) part

    cos(3x^2+x)(6x-1)

    not sure how to tidy up

    i wrote (6x-1)cos(3x^2+x)


  • Registered Users Posts: 2,604 ✭✭✭xOxSinéadxOx


    1fahy4 wrote: »
    You differentiate the sin part and the angle separately...

    So you get cos(3x^2+x) and then differentiate what's inside the brackets. So it's cos(3x^2+x)(6x+1)

    thanks!! :) I think that's what I did :cool:

    and lads I haven't a clue what any of ye are on about for 2. (c) guess I just wasn't made for the (c) parts


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  • Registered Users Posts: 174 ✭✭BLARG


    Nihilist21 wrote: »
    That was the matrix I got, pretty sure it's right. However to raise it to the power of 17, it would have been A^3 5 times which was the diagonal matrix, then multiply by A^2.

    (A^3)^14 = A^17
    The answer I think was
    (1 0)
    (0 1)


  • Moderators, Society & Culture Moderators Posts: 12,524 Mod ✭✭✭✭Amirani


    kevogy wrote: »
    cos(3x^2+x)(6x-1)

    not sure how to tidy up

    i wrote (6x-1)cos(3x^2+x)

    That's the way.


  • Registered Users Posts: 2,698 ✭✭✭Risteard


    BLARG wrote: »
    (A^3)^14 = A^17
    The answer I think was
    (1 0)
    (0 1)

    That's what I got.


  • Registered Users Posts: 528 ✭✭✭ayapatrick


    Chain rule...
    well **** it anyway!
    ah i left it as sin 3x^2 - sin x and diffed it!


  • Closed Accounts Posts: 407 ✭✭OxfordComma


    ****e! I screwed up b(ii) of the matrix question.... Damn! I thought I'd gotten full marks in that question :(


  • Registered Users Posts: 11,440 ✭✭✭✭Piste


    Oh no, for the chain rule yoke I thought Sinu becomes ucosu and you multiply that by du/dx so I got (6x-1)(3X^2+x)cos(3x^2+x)


  • Closed Accounts Posts: 189 ✭✭kevogy


    question 7 c part i
    how do you u show root is between 2 and 3?

    i got dy/dx

    solved the quadratic
    got x = 1


  • Registered Users Posts: 2,604 ✭✭✭xOxSinéadxOx


    kevogy wrote: »
    question 7 c part i
    how do you u show root is between 2 and 3?

    i got dy/dx

    solved the quadratic
    got x = 1

    newton raphson


  • Registered Users Posts: 11,440 ✭✭✭✭Piste


    You find f(2) and f(3) and if the sign changes between them the root lies between them.


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  • Registered Users Posts: 908 ✭✭✭Overature


    kevogy wrote: »
    i added up what i thought i got right and put over 600

    160
    ---- multiply by 100
    600

    around 26 %

    is this 26% of the entire maths exam?


    its 300 marks per paper. you should have got 160 over 300 or something


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