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Maths HL P 1 - aftermath

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Comments

  • #332
    Duncannon
    Closed Accounts Posts: 37 ✭Duncannon


    JamesJB wrote: »
    Thanks for the reply :cool: I sure hope so, I mean it is pretty much accurate I surmise. If they have the same slope it is fair to say they are the same tangent, no? I realise I should've found the actual tangent I just literally forgot, I've been doing that in a few tests...Hoping for an A though since I don't want to go down from the mocks, which were far harder than this imo!
    if you get the equation of the tangent at the 2 points you get the same line


  • #333
    Duncannon
    Closed Accounts Posts: 37 ✭Duncannon


    Deleted User wrote: »
    Yeah, as far as I can see because p is squared it will always be greater than 0 (or -1 if you moved that over like me).
    answer is correct perfect squares are always positive


  • #334
    Duncannon
    Closed Accounts Posts: 37 ✭Duncannon


    Victoria. wrote: »
    I stupidly forgot to put down the make and model of my calculator :(
    Was so stressed. Just opened the paper. Does anyone know if it is a problem?
    its not a problem


  • #335
    JamesJB
    Closed Accounts Posts: 143 ✭✭JamesJB


    Duncannon wrote: »
    if you get the equation of the tangent at the 2 points you get the same line

    Thanks, yeah I know - see I just did the slope idea and said they would be the same. Then, since I did that question 3rd, I said 'ah I'll come back and just do the eqn of the line after I've done the others.... BIG mistake. I just hope they'll give me the majority of the marks for doing like, what, more than half of what they wanted?


  • #336
    JamesJB
    Closed Accounts Posts: 143 ✭✭JamesJB


    I was just looking at one answer given here for 4 (c) (iii)

    I think I might've got a different answer. I used 3(n/6(n + 1)(2n + 1) + n) (since you bring the summation into the brackets).

    Then I did the sum from 1-30 = 3(n/6)(31)(61) + 30 = 28395
    and then from 1-11 = 1529

    Then I took the smaller away from the bigger and got 26866. I thought I had the right method but it seems I've gone wrong somewhere...Any ideas?


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  • #337
    mark.oc
    Registered Users, Registered Users 2 Posts: 52 ✭✭mark.oc


    JamesJB wrote: »
    I was just looking at one answer given here for 4 (c) (iii)

    I think I might've got a different answer. I used 3(n/6(n + 1)(2n + 1) + n) (since you bring the summation into the brackets).

    Then I did the sum from 1-30 = 3(n/6)(31)(61) + 30 = 28395
    and then from 1-11 = 1529

    Then I took the smaller away from the bigger and got 26866. I thought I had the right method but it seems I've gone wrong somewhere...Any ideas?
    It's the sum from 1-10 you take away in order to get your answer inclusive of 11.


  • #338
    EuropeanSon
    Registered Users, Registered Users 2 Posts: 2,819 ✭✭✭EuropeanSon


    JamesJB wrote: »
    I was just looking at one answer given here for 4 (c) (iii)

    I think I might've got a different answer. I used 3(n/6(n + 1)(2n + 1) + n) (since you bring the summation into the brackets).

    Then I did the sum from 1-30 = 3(n/6)(31)(61) + 30 = 28395
    and then from 1-11 = 1529

    Then I took the smaller away from the bigger and got 26866. I thought I had the right method but it seems I've gone wrong somewhere...Any ideas?
    Should've taken away the sum from 1-10 I think. 11 was included.


  • #339
    EuropeanSon
    Registered Users, Registered Users 2 Posts: 2,819 ✭✭✭EuropeanSon


    mark.oc wrote: »
    It's the sum from 1-10 you take away in order to get your answer inclusive of 11.
    Lol you got there first.


  • #340
    JamesJB
    Closed Accounts Posts: 143 ✭✭JamesJB


    mark.oc wrote: »
    It's the sum from 1-10 you take away in order to get your answer inclusive of 11.

    AHA. I see now, thanks. It's just a small enough blunder in any case. Quite literally an arithmetic one so what, - a few marks :rolleyes: I think I still have 6 other questions with near (if not almost definitely) full marks. Hoping marking scheme won't somehow screw me over but oh well, I'm happy.


  • #341
    Duncannon
    Closed Accounts Posts: 37 ✭Duncannon


    MollyJayne wrote: »
    Ok. In reply to everything...

    It was a very nice paper, and I think paper two will be the same!

    1. c) iii) so annoyed! I got b=-4 and d=6, but somehow I made c=-3-b = c=-3-4=7, when it should have been c=-3+4=1...only realised now! Kept trying to figure out what I'd done wrong... I'd decided to change d to -10 so it would fit the sequence, but it didn't fit the equation =[
    The right answers are definitely -4, 1, 6 as they fit the sequence and the equation...

    Another controversial issue...
    6. b) ii) It's definitely a curve. It says in the question that its a curve. Yup, parametric equations of a CURVE.
    I don't know the answer though... I was going to say that its increasing but if its a curve...it curves!

    I thought question 8 was lovely! Didn't quite get the last part of c out 'cause I ran out of time (shouldn't have kept checking that question 1!) but should get most of the marks for it...

    I think I got atleast 65% in that paper, and I always find paper two easier so I'm really hoping for a B at this stage!

    the "curve" was
    the line 2x-5y+1=0
    the numbers in 1c were-4,1,6


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  • #342
    EuropeanSon
    Registered Users, Registered Users 2 Posts: 2,819 ✭✭✭EuropeanSon


    http://en.m.wikipedia.org/wiki/Line_(geometry)?wasRedirected=true
    In Euclidean geometry, a line is a straight curve

    So a curve does NOT have to be "curvey".

    Hope that settles things.


  • #343
    Duncannon
    Closed Accounts Posts: 37 ✭Duncannon


    zam wrote: »
    For alphaxbeta i got ±4
    For alpha+beta i got 0 (which i think is wrong!)
    alpha x beata is +4 alpha +beata is 2


  • #344
    JamesJB
    Closed Accounts Posts: 143 ✭✭JamesJB


    Anyone use just regular simultaneous eqns for the matrix question? I wasn't in the mood for doing it out the pre/post multiplication way. Got the same answers obviously but I have this idea that they'll somehow try say you had to use matrix methods even if it didn't specify...


  • #345
    Duncannon
    Closed Accounts Posts: 37 ✭Duncannon


    JamesJB wrote: »
    Anyone use just regular simultaneous eqns for the matrix question? I wasn't in the mood for doing it out the pre/post multiplication way. Got the same answers obviously but I have this idea that they'll somehow try say you had to use matrix methods even if it didn't specify...
    they just said find x and y you can do it anyway, matrices, simultaneous equations ,both methods are fine the answers are x = 4, y = 2,


  • #346
    JamesJB
    Closed Accounts Posts: 143 ✭✭JamesJB


    Duncannon wrote: »
    they just said find x and y you can do it anyway, matrices, simultaneous equations ,both methods are fine the answers are x = 4, y = 2,

    That's what I got anyway :cool:


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