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In article <[EMAIL PROTECTED]>,
ZHANG Yan <[EMAIL PROTECTED]> wrote:
>Suppose that d is positive integer, i.e. d=1,2,3...
>A function is defined as follows.
>C(d)=C1(d)+C2(d)
>Now, I have to proof that there exists an optimal d, see d_{op},
>leading to minimum C(d). And also I have to find an algorithm to find
>d_{op}.
>I am able to proof that C1(d) is decreasing function of d, and C2(d)
>is increasing function of d. Note that no closed-form expression for
>C1(d) or C2(d), or even has closed-form, its first and second
>derivative is extremely difficult to obtain.
Derivatives? For a function defined only on positive integers?
>Could you plz give some suggestions to proceed? Many thanks in
>advance.
You haven't given us enough information to do this.
Robert Israel [EMAIL PROTECTED]
Department of Mathematics http://www.math.ubc.ca/~israel
University of British Columbia
Vancouver, BC, Canada V6T 1Z2
