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bmi5-Regular Member
5-Regular Member
March 20, 2012

How to set the third and fourth arguments of root function?

  • March 20, 2012
  • 2 replies
  • 4288 views

Hi Expert,

Here is a piecewise continuos function. I can get the two root by root function. But the third root with an error "The function values on the end points must be of opposite signs." How can I set he third and fourth arguments of root function?

root_function.jpg

    2 replies

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    wayne12-Amethyst
    12-Amethyst
    March 20, 2012

    Three options, 1) symbolic,  2) ployroot  3) try finding root of M(x)/M'(x), but I guess root has trouble because the function does not cross the axis.

    tmp5.gif

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    bmi5-Regular MemberAuthor
    5-Regular Member
    March 21, 2012

    Hi Wayne,

    Thanks for your help.

    About the piecewise function, we know M(200)=0. The root x=200 is existing. But the root(f,x,a,b)  should be monotonic function in the neighbourhood of the root value. So we can use ployroot function resolving the special root.

    Thanks again.

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