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Why Root[f] sometimes remains unevaluated even for a cubic polynomial f ?

According to my understanding for polynomials of degree lower than 5 the solution should always be expressed in terms of radicals. My version of Mathematica is 10.0.2.0.

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POSTED BY: Ulrich Mutze
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You can use ToRadicals to convert it to the traditional notation with radicals:

ToRadicals@Root[1 - #1^2 + #1^3 &, 1]

Yes. You can write the root of any polynomial of 5 or lower with radicals. But very often you don't want to.

  • Sometimes it's just hard to read.
  • Floating Point issues. As you may know, the standard quadratic formula taught in highschool can be a floating point disaster. So it's not clear you always want to immediately convert it into an expression made up of radicals.
POSTED BY: Sean Clarke

Thank you Sean, I was not aware of function ToRadicals. This solves my problem.

POSTED BY: Ulrich Mutze
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