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    (Original post by SkylineGTR)
    do we need to know algebraic division? i don't remeber needing it any paper i've done recently
    yes we do.
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    (Original post by mik1a)
    na. Don't do d^3y/dx^3. Point of inflection is when the gradient (dy/dx) = 0 and the change in gradient (d²y/dx²) = 0 as well.

    exactly therefore no point in d^3 it
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    ok thanks. i think i know it anyway...
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    ok guys do any of you use these equations to work out the trig equations:

    cos x = +/- PV +360N
    sinx = PV +180n
    Tanx = (-1)^n PV + 180n
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    (Original post by TheWolf)
    ok guys do any of you use these equations to work out the trig equations:

    cos x = +/- PV +360N
    sinx = PV +180n
    Tanx = (-1)^n PV + 180n
    nope! lol.. wtfa are they? looks remotely like pressure laws!
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    wow never seen them before...

    i use:

    Sin X = X1 + 360n AND Sin X = (180 - X1) + 360n
    Cos X = + X1 + 360n
    Tan X = X1 + 180n

    X1 is the calculator value...
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    Wait I found out for sure what a point of inflection is:

    "the condition for a point of inflexion is the f'(x)=0, f''(x)=o but f'''!=0"

    This was in the heinmann textbook p141.

    So we do need to know it if you do edexcel.
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    (Original post by Bebop)
    Wait I found out for sure what a point of inflection is:

    "the condition for a point of inflexion is the f'(x)=0, f''(x)=o but f'''!=0"

    This was in the heinmann textbook p141.

    So we do need to know it if you do edexcel.
    Hmm. It's meant to be f'''(x) =/= 0 I think, but I guess you're right. Not too hard to rember.
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    (Original post by mik1a)
    nope! lol.. wtfa are they? looks remotely like pressure laws!
    its incredibly useful + quick to do no more cast diagrams
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    (Original post by SkylineGTR)
    wow never seen them before...

    i use:

    Sin X = X1 + 360n AND Sin X = (180 - X1) + 360n
    Cos X = + X1 + 360n
    Tan X = X1 + 180n

    X1 is the calculator value...
    thats the same as mine! basically with PV being the caluclator value
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    (Original post by TheWolf)
    thats the same as mine! basically with PV being the caluclator value
    your sine and cos ones look different to me! :confused:
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    (Original post by SkylineGTR)
    your sine and cos ones look different to me! :confused:
    cos is the same! sine is different but im sure both works - mine definitely
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    sorry, i meant tan instead of cos

    what do you mean by (-1)^n PV + 180n :confused: -1 to the n?
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    (Original post by mik1a)
    Hmm. It's meant to be f'''(x) =/= 0 I think, but I guess you're right. Not too hard to rember.
    f'''(x) =/= 0

    He wrote:
    f'''(x) != 0


    It's the same thing.
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    (Original post by SkylineGTR)
    sorry, i meant tan instead of cos

    what do you mean by (-1)^n PV + 180n :confused: -1 to the n?
    yes -1 to the n makes it positive or negative
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    Can anyone help with either of these differentiation questions?
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    guys we need to know the proof for quadratic formula which one is it?
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    (Original post by TheWolf)
    guys we need to know the proof for quadratic formula which one is it?
    Which one is what? The quadratic formula?

    x = (-b ± √b² - 4ac)/2a


    Edit: I see what you mean now and I don't know the answer. Sorry.
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    (Original post by RDoh)
    Can anyone help with either of these differentiation questions?
    i think for first one you differentiate and find minimum maximum points then draw curve
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    are proof of quadratic formula and a.p /g.p the only ones we need to know?
    I don't know which proof for quadratic formula it is though
 
 
 
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