Advertisement
If you have a new account but are having problems posting or verifying your account, please email us on hello@boards.ie for help. Thanks :)
Hello all! Please ensure that you are posting a new thread or question in the appropriate forum. The Feedback forum is overwhelmed with questions that are having to be moved elsewhere. If you need help to verify your account contact hello@boards.ie

!! Maths HL paper 1 2016 - Before and After

Options
12357

Comments

  • Options
    #122
    emersyn
    Registered Users Posts: 430 ✭✭emersyn


    How are you all able to remember exactly what you got?? I haven't a notion of what any of my answers were


  • Options
    #123
    Edrees98
    Registered Users Posts: 142 ✭✭Edrees98


    DownOneTourist wrote: »
    well i got your average height! And i think i did the inverse function wrong. Can anyone explain how to do that inverse. and i totally did the radius rate and suface area questions wrong

    For the inverse, you let the function equal y, then you try and get the x independent. When that is done replace the y with an x and there ya go.


  • Options
    #124
    DublinArnie
    Closed Accounts Posts: 2,823 ✭✭✭DublinArnie


    DownOneTourist wrote: »
    well i got your average height! And i think i did the inverse function wrong. Can anyone explain how to do that inverse. and i totally did the radius rate and suface area questions wrong

    That average height is impossible because if you graph the function it's max is like 24 I think.

    You guys made the same mistake like I did by forgetting to multiply your final answer by 1/b-a. I saw it and corrected it in the end.

    Average height is 16.66 I think? Makes more sense.


  • Options
    #125
    Appmaths97
    Registered Users Posts: 28 ✭Appmaths97


    how were you supposed to show that 3x-2 was injective ?


  • Options
    #126
    luftmensch
    Closed Accounts Posts: 140 ✭✭luftmensch


    Does anyone know whether or not you will be penalised for not including units in your answers?


  • Advertisement
  • Options
    #127
    themadscone
    Registered Users Posts: 3 ✭themadscone


    Anyone know when provisional marking schemes go up? Currently bricking it as i forgot to work out the point the line is approching in q8... Just filled in the table and moved on:( hoping its not worth too much...


  • Options
    #128
    luftmensch
    Closed Accounts Posts: 140 ✭✭luftmensch


    Appmaths97 wrote: »
    how were you supposed to show that 3x-2 was injective ?

    I plotted it, and then used the horizontal line test.


  • Options
    #129
    skippy1977
    Registered Users Posts: 284 ✭✭skippy1977


    themadscone wrote: »
    Anyone know when provisional marking schemes go up? Currently bricking it as i forgot to work out the point the line is approching in q8... Just filled in the table and moved on:( hoping its not worth too much...

    Marking scheme won't go up until the day the Leaving Cert results come out...


  • Options
    #130
    luftmensch
    Closed Accounts Posts: 140 ✭✭luftmensch


    themadscone wrote: »
    Anyone know when provisional marking schemes go up? Currently bricking it as i forgot to work out the point the line is approching in q8... Just filled in the table and moved on:( hoping its not worth too much...

    After the results I think :)


  • Options
    #131
    skippy1977
    Registered Users Posts: 284 ✭✭skippy1977


    DublinArnie wrote: »
    That average height is impossible because if you graph the function it's max is like 24 I think.

    You guys made the same mistake like I did by forgetting to multiply your final answer by 1/b-a. I saw it and corrected it in the end.

    Average height is 16.66 I think? Makes more sense.

    Yep that's the answer.


  • Advertisement
  • Options
    #132
    Appmaths97
    Registered Users Posts: 28 ✭Appmaths97


    luftmensch wrote: »
    I plotted it, and then used the horizontal line test.
    It was such a stupid question because it the function is linear it is always injective.


  • Options
    #133
    emersyn
    Registered Users Posts: 430 ✭✭emersyn


    luftmensch wrote: »
    I plotted it, and then used the horizontal line test.

    I did this too and I just realised that I didn't label which question the graph was for on the graph paper - does anyone know if this will matter? That graph was the only thing I wrote on the page and it was the only extra page I handed up and in the space given on the exam paper itself I wrote 'SEE GRAPH PAPER'


  • Options
    #134
    pseudorachel
    Registered Users Posts: 26 ✭pseudorachel


    luftmensch wrote: »
    Does anyone know whether or not you will be penalised for not including units in your answers?

    you'll be docked a mark if you leave out the units but there wasn't that many on the paper anyway


  • Options
    #135
    skippy1977
    Registered Users Posts: 284 ✭✭skippy1977


    emersyn wrote: »
    I did this too and I just realised that I didn't label which question the graph was for on the graph paper - does anyone know if this will matter? That graph was the only thing I wrote on the page and it was the only extra page I handed up and in the space given on the exam paper itself I wrote 'SEE GRAPH PAPER'

    I'd say you'll be grand, the examiner should cop this. Especially if you wrote it on the exam.


  • Options
    #136
    Edrees98
    Registered Users Posts: 142 ✭✭Edrees98


    DublinArnie wrote: »
    That average height is impossible because if you graph the function it's max is like 24 I think.

    You guys made the same mistake like I did by forgetting to multiply your final answer by 1/b-a. I saw it and corrected it in the end.

    Average height is 16.66 I think? Makes more sense.

    So did I ...... Most we can lose is 2 I hope.


  • Options
    #137
    luftmensch
    Closed Accounts Posts: 140 ✭✭luftmensch


    emersyn wrote: »
    I did this too and I just realised that I didn't label which question the graph was for on the graph paper - does anyone know if this will matter? That graph was the only thing I wrote on the page and it was the only extra page I handed up and in the space given on the exam paper itself I wrote 'SEE GRAPH PAPER'

    Fuuuuuuuuuuuuu...

    I just realised that I never wrote the question number for any of the work I did on the extra spaces at the back.

    :(:(

    Will i be penalised for this. One of the questions I did at the back was the differentiation from first principles. I got it wrong the first time so I re-did at the back. No labels though :(

    Would the examiner be cool about it? I mean it's obvious what question it is right?


  • Options
    #138
    DublinArnie
    Closed Accounts Posts: 2,823 ✭✭✭DublinArnie


    You can also prove it's injective by subbing in different outputs and proving they only have one input.


  • Options
    #139
    Edrees98
    Registered Users Posts: 142 ✭✭Edrees98


    DublinArnie wrote: »
    You can also prove it's injective by subbing in different outputs and proving they only have one input.

    I did that and the graph yolk. Weird question though.
    luftmensch wrote: »
    Fuuuuuuuuuuuuu

    I just realised that I never wrote the question number for any of the work I did on the extra spaces at the back.

    :(:(

    You shouldn't really lose marks.


  • Options
    #140
    BrownTrout
    Closed Accounts Posts: 216 ✭✭BrownTrout


    Handy enough paper, think I got everything bar the angle of the basketball.

    Probably means it will be marked very harshly, everyone seems to be happy with it...


  • Options
    #141
    legocrazy505
    Closed Accounts Posts: 691 ✭✭✭legocrazy505


    BrownTrout wrote: »
    Handy enough paper, think I got everything bar the angle of the basketball.

    Probably means it will be marked very harshly, everyone seems to be happy with it...

    I know that's my worry about it. Got to keep the bell curve alive.


  • Advertisement
  • Options
    #142
    Appmaths97
    Registered Users Posts: 28 ✭Appmaths97


    what's the derivative of sin (1 divided by x)
    is it -1 over x squared by cos(1 divided by x)


  • Options
    #143
    DublinArnie
    Closed Accounts Posts: 2,823 ✭✭✭DublinArnie


    Appmaths97 wrote: »
    what's the derivative of sin (1 divided by x)
    is it -1 over x squared by cos(1 divided by x)

    I did the product rule since it was x multipled by the trig.

    From memory, I think I got -x^-1cos1/x + xsin1/2

    I think I messed that question up to be honest.


  • Options
    #144
    skippy1977
    Registered Users Posts: 284 ✭✭skippy1977


    Very nice paper. Unreal straight forward opening 6 questions, no tricks or difficult wording.
    Q7 was lovely, you couldn't get a more straight forward rate of change question. (b) (i) was Junior Cert level and the only thing in part (ii) was whether people would spot that 'average height' means integrate the function from 0 to 10 and divide times by 1/b-a.
    Q8 was a bit tricky but okay...not dissimilar to questions people would have done before (last years plane landing, the bridge question on another sample). (b) part was just substitution...working with logs at the end.
    Q9 looked harder than it was...once you established what numbers where in the geometric sequence you just had to apply...Sn and sum to infinity formulae.

    Overall I think people will be happy...don't worry about people saying that things will be marked harder....if you got questions right or mostly right they will still be right!

    No learned stuff...so expect a bit in Paper 2.


  • Options
    #145
    malnurtured
    Registered Users Posts: 107 ✭✭malnurtured


    DublinArnie wrote: »
    I did the product rule since it was x multipled by the trig.

    From memory, I think I got -x^2cos1/x + xsin1/2

    I think I messed that question up to be honest.

    Wouldn't it be (-x^-2)cos(1/x) + xsin(1/x)?

    The derivative of 1/x (x to the negative one) is -x^-2 right? Multiply that in to the cos(1/x)?

    I got my answer for that as -0.77. Anyone else?


  • Options
    #146
    DublinArnie
    Closed Accounts Posts: 2,823 ✭✭✭DublinArnie


    malnurtured wrote: »
    Wouldn't it be (-x^-2)cos(1/x) + xsin(1/x)?

    The derivative of 1/x (x to the negative one) is -x^-2 right? Multiply that in to the cos(1/x)?

    I got my answer for that as -0.77. Anyone else?

    Yeah, but when you multiply x^-2 with x you get x^-1 because you add/minus the powers.

    Is that correct? I'm losing it :o.

    Ah ****e, I meant to write -x^-1cos1/2 + xsin1/x in the post above.


  • Options
    #147
    luftmensch
    Closed Accounts Posts: 140 ✭✭luftmensch


    luftmensch wrote: »
    Fuuuuuuuuuuuuu...

    I just realised that I never wrote the question number for any of the work I did on the extra spaces at the back.

    :(:(

    Will i be penalised for this. One of the questions I did at the back was the differentiation from first principles. I got it wrong the first time so I re-did at the back. No labels though :(

    Would the examiner be cool about it? I mean it's obvious what question it is right?

    Actually, does anyone know if I could/should write a note on Mondays paper 2 indicating the unlabelled questions I did on the back of paper 1?


  • Options
    #148
    malnurtured
    Registered Users Posts: 107 ✭✭malnurtured


    DublinArnie wrote: »
    Yeah, but when you multiply x^-2 with x you get x^-1 because you add/minus the powers.

    Is that correct? I'm losing it :o.

    Yeah that's right, I can't remember if I did that or not, lol. Did you get -0.77 for the bit where you had to sub in afterwards?


  • Options
    #149
    DublinArnie
    Closed Accounts Posts: 2,823 ✭✭✭DublinArnie


    malnurtured wrote: »
    Yeah that's right, I can't remember if I did that or not, lol. Did you get -0.77 for the bit where you had to sub in afterwards?

    I remember getting a double decimal like that, 95% confidence interval that I'm sure.


  • Options
    #150
    Seaaan
    Registered Users Posts: 626 ✭✭✭Seaaan


    Reading everyone's confidence just makes me feel worse :( For the basketball angle one I just did tan inverse of opposite over adjacent and got 50 something, what's this about slopes??


  • Advertisement
  • Options
    #151
    malnurtured
    Registered Users Posts: 107 ✭✭malnurtured


    DublinArnie wrote: »
    I remember getting a double decimal like that, 95% confidence interval that I'm sure.

    Ah I'll get most of the marks, be grand. Was hoping for a B3 going in, definitely got that at least. Roll on P2
    Seaaan wrote: »
    Reading everyone's confidence just makes me feel worse :( For the basketball angle one I just did tan inverse of opposite over adjacent and got 50 something, what's this about slopes??

    I did opposite over adjacent too, was that not right? Seemed to be. I got like 34 degrees though I may have mixed up the x and y co-ords, hilariously enough


Advertisement