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    hi,

    i was revising some a level maths and i did a question in which my solution came to:

    0.5ln (3+/- sqrt8)

    now this is correct but the back of the book has:

    +/- 0.5ln(3+sqrt8)

    i tried playing around with the former but couldn't find a justifiable way of getting it to the second form, but they give the same end result. i.e. basically i don't know how to take out the +/- from before sqrt (8) to outside the expression without doing anything to the 3 at the same time.

    many thanks in advance,

    P
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    1/(3 + sqrt 8) = 3 - sqrt 8, right?
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    (Original post by generalebriety)
    1/(3 + sqrt 8) = 3 - sqrt 8, right?
    its the simplest of things that one misses out - surd manipulation! thanks - i get it now
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    Aye. I thought it was a mistake at first, posted, and then quickly deleted my post to hide the evidence when I realised.
 
 
 
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Updated: August 21, 2007

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