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The 2010, Honorary Member Welcoming, Undergraduate Degree Results Chat Thread Mk. IV Watch

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    (Original post by Smeh)
    At least you'll have something to take your mind off exam results.
    If you and A_master actually make it i'll...i'll...hmm what should I do?
    you should do FFF too!

    or maybe FFM :perv:
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    (Original post by dichr0ic)
    you should do FFF too!

    or maybe FFM :perv:
    :rofl:

    See this is the type of banter I'd be rofling at irl
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    (Original post by dichr0ic)
    you should do FFF too!

    or maybe FFM :perv:
    :coma:

    Sounds like fun :perv:
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    (Original post by sil3nt_cha0s)
    I got from y" + 6y' + 10 = 20

    down to

    y = Ae^(-3x) + Be^(-3t) + 20

    but wolfram says the answer is y = Ae^(-3x)sinx + Be^(-3t)cosx + 2

    why did they divide the last term by 10 and add in a sin and a cos? :emo:

    Total BS :facepalm:

    Well not totally, but you're including t's in there again and that's wrong.

    (Original post by sil3nt_cha0s)
    how do I do this differential equation: y" + 6y' + 10y = 20

    when I get to t^2 + 6t + 10 and it won't factorise how do I do it? no idea
    So solve t^2+6t+10=0. Have you heard of imaginary numbers??

    t= -3+i, -3-i

    So this gives the complementary function:
    y=e^{-3x}(A\cos(x)+B\sin(x))

    Now you need to find the particular integral. The RHS=20, so we can guess that it is of the form y=Cx^2+Dx+E.

    Differentiate twice, sub into the original ODE, equate coefficients and solve C/D/E. The general solution = complementary function + particular integral.

    Perhaps you should search for an old FP book (FP1 or 2 - I can't remember) or 'An Introduction to Ordinary Differential Equations' by Robinson.

    http://opac.warwick.ac.uk/search~S1/i?0521533910

    That's the search for it in our library.
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    Check my rad post count :cool:
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    (Original post by Loz17)
    :coma:

    Sounds like fun :perv:
    :cool:

    it's the national pastime of sierra leone. i've done a couple.

    it's a bit weird though. someone inevitably gets left out.
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    (Original post by dichr0ic)
    you should do FFF too!

    or maybe FFM :perv:
    :coma:
    Ok i'll do it.
    Just...gimme a few minutes...:sexface:
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    (Original post by A_master)
    Check my rad post count :cool:
    999 or your true one of 3164? :p:
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    (Original post by A_master)
    Check my rad post count :cool:
    You've only made 999 'possibly useful' posts.
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    (Original post by A_master)
    Check my rad post count :cool:
    :cool: :yep:

    your post count belies your chat thread activity :smug:
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    (Original post by A_master)
    Check my rad post count :cool:
    :yep: well played
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    (Original post by Loz17)
    999 or your true one of 3164? :p:
    :emo:
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    (Original post by TheTallOne)
    You've only made 999 'possibly useful' posts.
    99% of those 999 are not useful :p:
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    (Original post by dichr0ic)
    :cool:

    it's the national pastime of sierra leone. i've done a couple.

    it's a bit weird though. someone inevitably gets left out.
    :coma: I wanna go there!

    I can imagine.

    Spoiler:
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    I've always wanted to try FFM if I'm honest. Its a fantasy that Toby and I both share but I am pertified of posible consequences
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    (Original post by A_master)
    :emo:
    You should see my true post count. 12k+ :sigh:
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    (Original post by Smeh)
    :coma:
    Ok i'll do it.
    Just...gimme a few minutes...:sexface:
    tbh i think the thread would be prefer it if you waited and did FFM.

    sincerely.
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    (Original post by Loz17)
    You should see my true post count. 12k+ :sigh:
    :rofl:

    What a lozer geddit? :p:
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    (Original post by A_master)
    :rofl:

    What a lozer geddit? :p:
    :rofl3:
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    (Original post by Loz17)
    :coma: I wanna go there!

    I can imagine.

    Spoiler:
    Show
    I've always wanted to try FFM if I'm honest. Its a fantasy that Toby and I both share but I am pertified of posible consequences
    indeed

    i've seen many a-thread in h&r (in my short time here :ninja:) of boyfriends choosing someone to have a threesome with, then the gf gets totally neglected, it's basically cheating

    i think the constituents of the couple should choose together, that way noone gets left behind, noone is left to slip away...
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    (Original post by TheTallOne)
    Total BS

    Well not totally, but you're including t's in there again and that's wrong.



    So solve . Have you heard of imaginary numbers??

    t= -3+i, -3-i

    So this gives the complementary function:


    Now you need to find the particular integral. The RHS=20, so we can guess that it is of the form .

    Differentiate twice, sub into the original ODE, equate coefficients and solve C/D/E. The general solution = complementary function + particular integral.

    Perhaps you should search for an old FP book (FP1 or 2 - I can't remember) or 'An Introduction to Ordinary Differential Equations' by Robinson.

    http://opac.warwick.ac.uk/search~S1/i?0521533910

    That's the search for it in our library.
    I got the answer finally :woo:

    still not getting why it's of the particular form

    or why a constant on the right has the particular form of a quadratic...

    but E = 2, C = 0 amd D = 0, to give that answer above, + 2

    :woo:
 
 
 
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