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Math Help - simple surd thing

  1. #1
    Senior Member furor celtica's Avatar
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    simple surd thing

    explain why 1/((sqrt3)-1) = 1/((sqrt3)-1) x ((sqrt3) +1)/((sqrt3) +1)
    i think the obvious answer is that ((sqrt3) +1)/((sqrt3) +1) = 1 but i dont know if thats the answer im supposed to be looking for...
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  2. #2
    MHF Contributor
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    Quote Originally Posted by furor celtica View Post
    explain why 1/((sqrt3)-1) = 1/((sqrt3)-1) x ((sqrt3) +1)/((sqrt3) +1)
    i think the obvious answer is that ((sqrt3) +1)/((sqrt3) +1) = 1 but i dont know if thats the answer im supposed to be looking for...
    That's exactly the reason. If you multiply a number by 1, you get what you started with.

    And from here, you can rationalise the denominator.
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  3. #3
    Senior Member Stroodle's Avatar
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    Either that or:

    \frac{1}{\sqrt{3}+1}\times \frac{\sqrt{3}+1}{\sqrt{3}+1}

    =\frac{(\sqrt{3}+1)}{(\sqrt{3}+1)(\sqrt{3}+1)}

    =\frac{1}{\sqrt{3}+1}
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  4. #4
    Senior Member furor celtica's Avatar
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    hahaha the whole time i was thinking 'damn i need to find something more complicated'
    thanks guys
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