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Thread: Cosine fixpoint

  1. May 23rd 2009, 07:28 AM #1
    espen180
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    Cosine fixpoint

    Is the cosine fixpoint (the solution to the equation x=\cos x) rational or irrational, and is it possible to prove it?
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  2. May 25th 2009, 01:01 AM #2
    Grandad
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    Rational or irrational

    Hello espen180
    Quote Originally Posted by espen180 View Post
    Is the cosine fixpoint (the solution to the equation x=\cos x) rational or irrational, and is it possible to prove it?
    I can't imagine that it could possibly be rational, but I have no idea how you might set about proving it!

    Grandad
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