Mullers Method or Parabolic Interpolation

This method approximates the function with a parabola. Contrary to the previous methods, three points are needed to estimate the parameters of the parabola. 

1) It is efficient at finding the roots of a polynomial with degree higher than 3. 

As the method approximates the function using a parabola, it is necessary to choose a solution from the two possible predictions. 

Except in the case of polynomial root-finding and complex roots, there are more efficient and easier-to-implement algorithms. 

The parabolic interpolation method is never used in the BzzMaA hbrary classes dedicated to root-finding. 

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