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    (Original post by darth_vader05)
    :bawling: you did that on purpose :hmpf: :p:
    No i didnt! .... :flute: loll :p:
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    (Original post by darth_vader05)
    my eyes are hurting but i dont want o go to sleep :p:

    np i made mine on there

    erm is it about £40?? :confused: :p: i cant remember :p:
    Lol same :p: and its nearly 4 loll so what time is sunrise? loll :p:

    just found out that my biology exam is actually 4 Hours long :afraid:

    loll :p: np
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    (Original post by Angel Interceptor)
    Meh, this is what I did:

    y = (x2 - 4)3

    dy/dx = 6x(x2 - 4)2

    d2y/dx2 = 24x2(x2 - 4)

    Anyhows, stationary points occur when dy/dx = 0, ie. 0 = 6x(x2 - 4)2, which can be simplified to 0 = 6(x - 2)2 + x(x + 2)2

    This gives x values of 2, 0 and 2, and corresponding y values of 0, -64 and -216, so you get the coordinates (2,0), (0,-64) and (-2,-216).
    d2/dx2 = 24x2(x2 - 4)

    Substituting the x values into the equation for d2y/dx2, we get 0, 0 and 0 (like you got), hence you cannot deduce anything from this apart from that at those coordinates, you have points of inflection. If you don't believe that, then have a look at the graph.

    PS. I hate typing out maths! It takes so long!
    ah so thats how you do ^2 :p: i know what you mean about typing maths :p:

    how can you deduce that they're points of inflexion without drawing a graph- or cant you? ( this is where i got stuck)

    btw thanks for the help
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    (Original post by SketchyCanvas)
    you can't change your mind :motz: :hmmm: :p:

    try to :hmpf: loll :p:
    i just did :eviltongue: :p:

    ok :angel: :p: haahahah
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    (Original post by darth_vader05)
    ah so thats how you do ^2 :p: i know what you mean about typing maths :p:

    how can you deduce that they're points of inflexion without drawing a graph- or cant you? ( this is where i got stuck)
    Tsk, n00bs know nothing! :p:

    Sketch the graph and see for yourself - it's an easy sketch.
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    (Original post by darth_vader05)
    i just did :eviltongue: :p:

    ok :angel: :p: haahahah
    well you cant :eviltongu :hmmm: :p:

    :battle: loll
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    (Original post by Angel Interceptor)
    Tsk, n00bs know nothing! :p:

    Sketch the graph and see for yourself - it's an easy sketch.

    :itsme: loll :p:
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    (Original post by SketchyCanvas)
    No i didnt! .... :flute: loll :p:
    :hmpf: :motz: this isnt over yet
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    (Original post by SketchyCanvas)
    Lol same :p: and its nearly 4 loll so what time is sunrise? loll :p:

    just found out that my biology exam is actually 4 Hours long :afraid:

    loll :p: np
    about sixish i think :ninja: :p: we have to be asleep before sunrise

    4 hours :eek: i thought it was 3???

    hehe
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    (Original post by SketchyCanvas)
    :itsme: loll :p:
    Oh dear, if you're finding that funny, it means that you're in need of some sleep....now! :p:
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    (Original post by Angel Interceptor)
    Tsk, n00bs know nothing! :p:

    Sketch the graph and see for yourself - it's an easy sketch.
    meh, you oldies think you know everything :hmpf: :p: (and i dont want to know if you do :hmmm: )

    thanks muchly appreciated- now i can sleep in peace :p: its a funny looking graph!
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    Anyhows, here's the graph if you're being a lazy sod! There are tiny fluctuations at the points of inflection, but it's not noticeable on this scale.

    Edit: This graph is actually quite pointless, anyhows the maths you've done shows you that there aren't any localised maxima or minima on it.
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    (Original post by SketchyCanvas)
    well you cant :eviltongu :hmmm: :p:

    :battle: loll
    since when? ^o) :p:

    :fight:
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    (Original post by darth_vader05)
    :hmpf: :motz: this isnt over yet
    :evil: its over, me win lol
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    (Original post by Angel Interceptor)
    Oh dear, if you're finding that funny, it means that you're in need of some sleep....now! :p:
    Lol i've gone giggly :eek: its cos of the sleepyness, makes me giggly :p:
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    (Original post by SketchyCanvas)
    Lol i've gone giggly :eek: its cos of the sleepyness, makes me giggly :p:
    Well, I prefer cheerful people anyway, so it doesn't bother me.
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    (Original post by darth_vader05)
    since when? ^o) :p:

    :fight:
    since now :cool: loll

    :boxing: :p:
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    (Original post by Angel Interceptor)
    Anyhows, here's the graph if you're being a lazy sod! There are tiny fluctuations at the points of inflection, but it's not noticeable on this scale.

    Edit: This graph is actually quite pointless, anyhows the maths you've done shows you that there aren't any localised maxima or minima on it.
    meh im lazy, but not that lazy

    so if d^2y/dx =0 its a point of inflexion?

    (cant be bothered with the sup thing :p: )
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    (Original post by Angel Interceptor)
    Well, I prefer cheerful people anyway, so it doesn't bother me.


    oo oo just remebered, can you lot fill this in please http://kevan.org/johari?name=Munise meh, im bored :p:
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    (Original post by SketchyCanvas)
    :evil: its over, me win lol
    its over when i say its over :vader:

    :rofl: im on a high aswell :p: i'm trying my bestest to not laugh loudly
 
 
 

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