STEP III 2012 Discussion Thread

Maths exam discussion - share revision tips in preparation for GCSE, A Level and other maths exams and discuss how they went afterwards.

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  1. fruktas's Avatar
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    Re: STEP III 2012 Discussion Thread
    (Original post by maksokio)
    I think there was a sentence omitted from question one, one that should read "where z=y^n*(something)" like in 2010 STEP II that they forgot to type another sentence about the Useless Eustace question about the range of value of the angles (0<θ<2π).

    It may be possible that someone can work out the value of z (as a function of y) by directly integrating the right hand side of the the formula given.
    I agree, but the thing is that without this info we couldnt do the question! I ended up saying let z = x^2/4 (without any explanation) in order to show the result given in Q1
  2. cpdavis's Avatar
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    Re: STEP III 2012 Discussion Thread
    (Original post by TheMagicMan)
    Not in my book. I've consulted about 25 offer holders and about 70% thought it was on the hard side


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    I think Farhan told me that it was a nice paper if you liked summing
  3. desijut's Avatar
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    Re: STEP III 2012 Discussion Thread
    I guess im alone when i say i did number 1 completely (Yes n=1 and n=-2)... But that's it. I did most of 6 and 7 (15+) and then 3 (not even) partial solutions (2,4,5), possibly about 5 marks each.

    By the way this is me being hopeful

    I personally thought it was harder than previous years, but im generally not a good judge of what an easy and hard paper is
    Last edited by desijut; 28-06-2012 at 16:44.
  4. TheMagicMan's Avatar
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    (Original post by maksokio)
    I think there was a sentence omitted from question one, one that should read "where z=y^n*(something)" like in 2010 STEP II that they forgot to type another sentence about the Useless Eustace question about the range of value of the angles (0<θ<2π).

    It may be possible that someone can work out the value of z (as a function of y) by directly integrating the right hand side of the the formula given.
    This was my opinion. I thought there was a sentence missing as they usually aren't so blunt at setting up the question


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  5. fruktas's Avatar
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    Re: STEP III 2012 Discussion Thread
    (Original post by B Jack)
    z=yn(dy/dx)2 , but I only worked that out after the exam :rolleyes:
    That isn't fair, ie a misprint!.. I wasted around 20 minute during the duration of the paper trying to answer it.
  6. maksokio's Avatar
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    Re: STEP III 2012 Discussion Thread
    (Original post by B Jack)
    I didn't do question 1, but I noticed z=(y^n)(dy/dx)^2
    I am afraid that can not be mate, since that wouldnt give (dy/dx)^3 that is contained in the right hand side.

    apologies for that, total nonsense
    Last edited by maksokio; 28-06-2012 at 18:05.
  7. B Jack's Avatar
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    Re: STEP III 2012 Discussion Thread
    (Original post by maksokio)
    I am afraid that can not be mate, since that wouldnt give (dy/dx)^3 that is contained in the right hand side.
    It's factored out, the dy/dx is
  8. desijut's Avatar
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    Re: STEP III 2012 Discussion Thread
    (Original post by maksokio)
    I am afraid that can not be mate, since that wouldnt give (dy/dx)^3 that is contained in the right hand side.
    You forget there was a dy/dx outside the brackets
  9. TheMagicMan's Avatar
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    (Original post by RacingPro97)
    I agree about Q1 - I was worrying this morning thinking that I might be the only person with a printing error or something!
    I sent an email to the teacher at my school who's a step problem writer... We'll see what he says... I would be shocked if it actually was a mistake


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  10. SParm's Avatar
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    Re: STEP III 2012 Discussion Thread
    Hmmm...I did 8 fully; everything but ii) on 2; everything but the a^3 bit on three; the first two proofs for four; and everything but the inequality on 7. Oh...and I solved first bit of 1 and got z = f(y) (lulwut?)...didn't go well for me. How would you rate my chances of getting a 1 ?_?...(anyone feel free to answer).
  11. fruktas's Avatar
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    Re: STEP III 2012 Discussion Thread
    (Original post by desijut)
    I guess im alone when i say i did number 1 completely (Yes n=1 and n=-2)... But that's it. I did most of 6 and 7 (15+) and then 3 (not even) partial solutions (2,4,5), possibly about 5 marks each.

    By the way this is me being hopeful

    I personally thought it was harder than previous years, but im generally not a good judge of what an easy and hard paper is
    Yeah, I worked that much out for Q1 that n was -2 or -1/2 cannot remember now, and first part was n =1
  12. Tobedotty's Avatar
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    Re: STEP III 2012 Discussion Thread
    I fully did the 3 summation questions (2,4? and 8) and then started 5 and 7. I agree it was quite nice if you like summation, I certainly enjoyed it
  13. B Jack's Avatar
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    Re: STEP III 2012 Discussion Thread
    People who did question 4, does 12-16ln2 sound like the answer you got for ii)?
  14. iluvmaths's Avatar
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    Re: STEP III 2012 Discussion Thread
    (Original post by TheMagicMan)
    I sent an email to the teacher at my school who's a step problem writer... We'll see what he says... I would be shocked if it actually was a mistake


    This was posted from The Student Room's iPhone/iPad App
    all u had to say was the n was 1. then sub in the formula for root(y). then solve a simple differential eqn. for the next part, n was 3 or 4. the formula for dz/dx was just a product of two differentials.
  15. fruktas's Avatar
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    Re: STEP III 2012 Discussion Thread
    I thought question 2, was sort of a 'typical' STEP question. They guided you through something, and asked you to repeat it all yourself for a different function
  16. maksokio's Avatar
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    Re: STEP III 2012 Discussion Thread
    It may be that I am being stupid here for some reason but I think that if z=y^n(dy/dx)^2 then dz/dx=ny^(n-1)(dy/dx)^2+2y^n(dy/dx)(d^2y/dx^2) when the formula reads dz/dx=ny^(n-1)(dy/dx)^3+2y^n(dy/dx)(d^2y/dx^2)
  17. fruktas's Avatar
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    Re: STEP III 2012 Discussion Thread
    (Original post by maksokio)
    It may be that I am being stupid here for some reason but I think that if z=y^n(dy/dx)^2 then dz/dx=ny^(n-1)(dy/dx)^2+2y^n(dy/dx)(d^2y/dx^2) when the formula reads dz/dx=ny^(n-1)(dy/dx)^3+2y^n(dy/dx)(d^2y/dx^2)
    the question did not have a cubed dy/dx it was squared
  18. Tobedotty's Avatar
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    Re: STEP III 2012 Discussion Thread
    (Original post by fruktas)
    I thought question 2, was sort of a 'typical' STEP question. They guided you through something, and asked you to repeat it all yourself for a different function
    I thought that took the piss tbh, I wanted to do something different instead of the same tedious thing again.
  19. maksokio's Avatar
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    Re: STEP III 2012 Discussion Thread
    Can someone that somehow did question 1 (with n=1 and n=-2) write it down? I am really interested to see how you worked with z.
  20. TheMagicMan's Avatar
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    Check what you've got


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