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FindRoot, suppressing complex interval-numbers

  • To: mathgroup at smc.vnet.net
  • Subject: [mg70870] FindRoot, suppressing complex interval-numbers
  • From: "Paul" <pw23 at gmx.net>
  • Date: Mon, 30 Oct 2006 05:32:57 -0500 (EST)

Hello,
I have the following problem:
Take the simple example

FindRoot[Sin[x] +2, {x, 1.656 10^8, 1.653 10^8, 1.658 10^8},
EvaluationMonitor :> AppendTo[xs, x]]

In the Help we can read: "FindRoot[lhs==rhs, {x, a, a_min, a_max}]
searches for a solution, stopping the search if x ever gets outside the
range a_min to a_max. "

But when I display xs I can see, that there are also two complex
numbers used.

This is a problem if I use a function (in my case a compiled one)
inside FindRoot, which only accepts real numbers.

So how can I suppress the using of complex numbers in FindRoot?

Best regards,
Paul

(Mathematica 5.2)


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