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     y= 2x(2x + 1)^(0.5)

    i used the chain rule and then the product rule to get:

     3x(2x + 1)^-0.5 + 3(2x + 1)^(0.5)

    But it doesn't seem to work! is that bit above wrong?

    if its hard to read, its to the power of 0.5
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    Is the question 2x\sqrt{2x + 1} ?
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    (2x)(2x+1)^-0.5 + 2(2x+1)^0.5
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    give me a sec to write it.

    edit - cksuper has got it
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    root(2x + 1) differentiates to 2(1/2)(2x + 1)^(-1/2) = (2x + 1)^(-1/2). Did you get that? Where are those threes coming from?
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    I get that both the 3s should be replaced by 2s.
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    just let the first part = u, the second = v
    Then carry out: uv' +vu'
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    (Original post by CKsuper1)
    (2)(2x)(2x+1)^-0.5 + 2(2x+1)^0.5

    why isn't it (2)(1/2)(2x)(2x + 1)^-0.5 + 2(2x + 1)^0.5?
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    because you square the differential which is 2 then factorise- or alternatively you can expand the bracket then simplify
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    yh...soz, just editted it...my mistake
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    (Original post by CKsuper1)
    (2x)(2x+1)^-0.5 + 2(2x+1)^0.5
    ok, how did i get the 3x instead of the  2x ?


    the question is  y= 3x(2x + 1)^0.5
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    argh, my fault, i wrote the question wrong!
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    becuase
    root(2x + 1) differentiates to 2(1/2)(2x + 1)^(-1/2) = (2x + 1)^(-1/2).
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    (Original post by DreamsComeTrue.)
    ok, how did i get the 3x instead of the  2x ?


    the question is  y= 3x(2x + 1)^0.5
    Ur Q above says 2x(2x + 1)^0.5....

    If it was 3x: 3x(2x+1)^-0.5 + 3(2x+1)^0.5
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    (Original post by shyamp)
    give me a sec to write it.

    edit - cksuper has got it
    hehe....soz
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    omg, i just subed x = 4 into my orignial equation which i thought was "wrong" and i got 13! which the right answer but i swear when i tried 3 times beofre i got the wring answer! sorry guys
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    i do appreciate your help anyway
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    no probz.....its good to see some easier questions lol....since I tend to be panicking over my own
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    (Original post by CKsuper1)
    no probz.....its good to see some easier questions lol....since I tend to be panicking over my own
    why? which module you doing at the moment?
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    (Original post by CKsuper1)
    no probz.....its good to see some easier questions lol....since I tend to be panicking over my own
    Have you done Analysis yet? :p: Q 3,5 and most of 1 down!!! For some reason last night at about 4am everything clicked after staring at it for hours LOL
 
 
 

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