Laguerre:

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   Finds the polynomial roots using Laguerre's method. There is a fix in
   place to force the return of real roots as Laguerre finds any root,
   real or imaginary.

   Since version 7.
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   Form:
   x = Laguerre(p, xGuess)
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   Inputs
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   p         (1,7)      Vector containing the coefficients of the polynomial. 
                        The coefficients are ordered as follows 
                        Sum p[i] x^i, i=0...mP
   xGuess    (1)        Initial guess for the root

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   Outputs
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   x         (1)        root

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