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    You have the differential equation below. Prove the thing next to that. I can't do it so don't ask me for help, have fun xx

    Edit: I now know how to do it. Alas, I still will not help to be evil
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    *Quietly returns to basic C4*
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    (Original post by Gome44)
    You have the differential equation below. Prove the thing next to that. I can't do it so don't ask me for help, have fun xx

    Edit: I now know how to do it. Alas, I still will not help to be evil
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    I guess set \ddot{\theta} = \frac{1}{2} \frac{d (\dot{\theta}^2)}{d\theta} and solve the first order ODE in \dot{\theta}^2, but I don't have time to do it now. Looks like you'll get an exponential and sins and coses though - and square roots, so it looks good to me
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    This reminds me of the pendulum equation maybe??
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    (Original post by Serine Soul)
    *Quietly returns to basic C4*
    Random... But Audrey is a goddess
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    But you already knew that :yep:
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    (Original post by Student403)
    Random... But Audrey is a goddess
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    But you already knew that :yep:
    PRSOM

    She's my WCW everyday :love:

    I genuinely aspire to be like her
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    (Original post by Serine Soul)
    PRSOM

    She's my WCW everyday :love:

    I genuinely aspire to be like her
    That's awesome :awesome:
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    (Original post by Louisb19)
    This reminds me of the pendulum equation maybe??
    Its a quadratically damped pendulum
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    (Original post by atsruser)
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    I guess set \ddot{\theta} = \frac{1}{2} \frac{d (\dot{\theta}^2)}{d\theta} and solve the first order ODE in \dot{\theta}^2, but I don't have time to do it now. Looks like you'll get an exponential and sins and coses though - and square roots, so it looks good to me
    Not the way I've been told to do it, but it looks like that would work
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    (Original post by Gome44)
    You have the differential equation below. Prove the thing next to that. I can't do it so don't ask me for help, have fun xx

    Edit: I now know how to do it. Alas, I still will not help to be evil
    Surely just solve it in the usual way: form the characteristic equation, guess a particular integral, etc.
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    ayy lmao
    is this FP2? two dots above the theta means second-order differential of theta right?
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    (Original post by Raees_Sharif)
    ayy lmao
    is this FP2? two dots above the theta means second-order differential of theta right?
    I think for OCR MEI it would be in the DE module, and other boards (aka boring ones) it would be in FP3.
    And yes, two dots means second derivative. It's a notation invented by Newton that's used mainly in mechanics.
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    (Original post by ConstatSententia)
    I think for OCR MEI it would be in the DE module, and other boards (aka boring ones) it would be in FP3.
    And yes, two dots means second derivative. It's a notation invented by Newton that's used mainly in mechanics.
    Nope, sadly despite the name OCR MEI's DE module is surprisingly bare. Only very basic things and it's obsessed with modelling rather than solving harder DEs.
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    (Original post by ConstatSententia)
    Surely just solve it in the usual way: form the characteristic equation, guess a particular integral, etc.
    Nope, be carful you have  \sin{\theta} .

    It's only solvable in terms of elliptic integrals I think (this is not what Gnome is asking for however).
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    (Original post by ConstatSententia)
    I think for OCR MEI it would be in the DE module, and other boards (aka boring ones) it would be in FP3.
    And yes, two dots means second derivative. It's a notation invented by Newton that's used mainly in mechanics.
    2nd order ODEs are covered in FP2 for Edexcel. You can't solve this with the methods that you learn at A-Level anyway.
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    (Original post by Louisb19)
    Nope, be carful you have  \sin{\theta} .

    It's only solvable in terms of elliptic integrals I think (this is not what Gnome is asking for however).


    (Original post by Louisb19)
    2nd order ODEs are covered in FP2 for Edexcel. You can't solve this with the methods that you learn at A-Level anyway.

    Mathematica says it's unsolvable.
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    (Original post by ConstatSententia)
    Mathematica says it's unsolvable.
    It is but only in terms of elliptic integrals.

    http://math.ucr.edu/home/baez/classical/pendulum.pdf
    http://mathworld.wolfram.com/Ellipti...FirstKind.html

    The question he is asking is not about solving it though so it doesn't matter .

    By the way the revolution is dead mate.
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    nunc exibo quia mathematica pervecta nescio.
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    (Original post by Louisb19)
    It is but only in terms of elliptic integrals.

    http://math.ucr.edu/home/baez/classical/pendulum.pdf
    http://mathworld.wolfram.com/Ellipti...FirstKind.html

    The question he is asking is not about solving it though so it doesn't matter .

    By the way the revolution is dead mate.
    While the normal pendulum equation is solvable with elliptic integrals, the quadratically damped pendulum is not unfortunately.

    Only numerical methods can be used to evaluate t at certain theta (incidentally I took this from one of my Matlab projects)
 
 
 
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