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P3 Integration Dude's Hard One! Who Can Crack It?! watch

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    i have the ans as e-2

    Does anyone want me to show them the whole method or are they ok?
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    (Original post by Bhaal85)
    Who are you trying to teach?
    I am trying to boast that i am capable of some maths!!!

    Trying to teach myself actually!!!
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    (Original post by mabs)
    someone show me the u and v dash method, geebee, d/dx x (wt is that???) - first line of working
    d(f(x))/dx means the differential of a function wrt. x
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    (Original post by Silly Sally)
    i have the ans as e-2

    Does anyone want me to show them the whole method or are they ok?

    yippeeeeeee i got it!! lol was just a bit blind so thought i did it wrong. i'm 18 soon too! yay
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    (Original post by wonkey)
    yippeeeeeee i got it!! lol was just a bit blind so thought i did it wrong. i'm 18 soon too! yay
    YAY!!! Well done!! I couldn't have one it without everyones hints though

    When are you 18?
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    (Original post by Silly Sally)
    YAY!!! Well done!! I couldn't have one it without everyones hints though

    When are you 18?

    yeah i would have messed up too. 20th u?
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    (Original post by wonkey)
    yeah i would have messed up too. 20th u?
    of june?

    Mine is 25th of july!!!! Can't wait!!!
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    ∫ ² ³ ± ÷ ° √ ∂ ∞ ≈ ≠ ≡ ≥ ≤ ø Ø ½ ¼ « » µ π

    ∫ (lnx)^2 dx = ∫ lnxlnx

    u=lnx
    du/dx=1/x

    dv/dx=lnx
    v=x(lnx-1)

    ∫ u.dv/dx = uv-∫ v.du/dx

    xlnx(lnx-1)-∫ x(lnx-1).1/x dx
    xlnx(lnx-1)-∫ lnx-1 dx
    xlnx(lnx-1)-(x(lnx-1)-x)
    xlnx(lnx-1)-(xlnx-2x)
    [xlnx(lnx-1)-xlnx+2x] between e and 1. Tell me its right.
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    (Original post by Silly Sally)
    of june?

    Mine is 25th of july!!!! Can't wait!!!
    yeah june!!
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    (Original post by Bhaal85)
    ∫ ² ³ ± ÷ ° √ ∂ ∞ ≈ ≠ ≡ ≥ ≤ ø Ø ½ ¼ « » µ π

    ∫ (lnx)^2 dx = ∫ lnxlnx

    u=lnx
    du/dx=1/x

    dv/dx=lnx
    v=x(lnx-1)

    ∫ u.dv/dx = uv-∫ v.du/dx

    xlnx(lnx-1)-∫ x(lnx-1).1/x dx
    xlnx(lnx-1)-∫ lnx-1 dx
    xlnx(lnx-1)-(x(lnx-1)-x)
    xlnx(lnx-1)-(xlnx-2x)
    [xlnx(lnx-1)-xlnx+2x] between e and 1. Tell me its right.
    Yep - that would give you the right ans - although i did it another way - but that doesnt matter cos in maths there area thousand ways to get from A to B
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    (Original post by Bhaal85)
    ∫ ² ³ ± ÷ ° √ ∂ ∞ ≈ ≠ ≡ ≥ ≤ ø Ø ½ ¼ « » µ π

    ∫ (lnx)^2 dx = ∫ lnxlnx

    u=lnx
    du/dx=1/x

    dv/dx=lnx
    v=x(lnx-1)

    ∫ u.dv/dx = uv-∫ v.du/dx

    xlnx(lnx-1)-∫ x(lnx-1).1/x dx
    xlnx(lnx-1)-∫ lnx-1 dx
    xlnx(lnx-1)-(x(lnx-1)-x)
    xlnx(lnx-1)-(xlnx-2x)
    [xlnx(lnx-1)-xlnx+2x] between e and 1. Tell me its right.
    Yep it is as:

    [elne(lne-1)-elne+2e] = e
    [1ln1(ln1-1)-1ln1+2] = 2

    Yah, three cheers for Bhaal.
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    (Original post by Silly Sally)
    Yep - that would give you the right ans - although i did it another way - but that doesnt matter cos in maths there area thousand ways to get from A to B
    Or e to 1.
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    (Original post by Bhaal85)
    Or e to 1.
    lol - yep indeedy
    • Thread Starter
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    waaaaaaaaaaaaaaaheeeeeeeeeeeey
 
 
 
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