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Math Help - Show that srt(2)+srt(3)-srt(5+2srt(6)) is rational/irrational

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    Show that srt(2)+srt(3)-srt(5+2srt(6)) is rational/irrational

    srt(2)+srt(3)-srt(5+2srt(6))

    Show that this is rational/irrational

    Can someone give me an idea of where to start?
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    Re: Show that srt(2)+srt(3)-srt(5+2srt(6)) is rational/irrational

    we know that sum / difference of two irrational numbers is irrational unless we are subtracting the same irrational number in which case the result will be 0. That should give you a beginning.
    Last edited by ibdutt; January 22nd 2014 at 08:18 PM.
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    Re: Show that srt(2)+srt(3)-srt(5+2srt(6)) is rational/irrational

    Ibdutt you are missing something?
    let r1 be a rational number and r2 another rational then r1+π is irrational and r2-π is also irrational ..but (r1+π)+(r2-π) IS A RATIONAL AND NOT IRRATIONAL number !!!
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    Re: Show that srt(2)+srt(3)-srt(5+2srt(6)) is rational/irrational

    Quote Originally Posted by MINOANMAN View Post
    Ibdutt you are missing something?
    let r1 be a rational number and r2 another rational then r1+π is irrational and r2-π is also irrational ..but (r1+π)+(r2-π) IS A RATIONAL AND NOT IRRATIONAL number !!!
    I'm sure ibdutt meant "subtracting the same irrational number PART".
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    Re: Show that srt(2)+srt(3)-srt(5+2srt(6)) is rational/irrational

    Hi,
    I assume "srt" means square root. I don't know how to give you a hint without answering the question. So the attachment gives a solution:

    Show that srt(2)+srt(3)-srt(5+2srt(6)) is rational/irrational-mhfnumbertheory6.png
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