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Math Help - condition number

  1. #1
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    condition number

    The relative condition number is defined here:
    Numerical Linear Algebra - Google Book Search

    In an example, I have that f(x) = exp(x). What is the relative condition number here?

    I assume it is x*exp(x)/exp(x) = x. Is this correct?
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  2. #2
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    Well, the site you link to gives the "relative condition number" as \frac{||J||||x||}{||f(x)||} and further notes that if f is a real valued function of a single real variable, that reduces to \frac{|f'(x)||x|}{|f(x)|}. In your example, f(x)= exp(x), f'(x) is also exp(x) so they cancel and your are almost correct- the relative condition number is |x|.
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