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Student Support Forum: 'Solving Polynomials' topicStudent Support Forum > General > "Solving Polynomials"

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Nick
09/19/09 4:58pm

I'm trying to generate exact real solutions to cubics and polynomials of higher degree, for example x^3+x^2-8x+1=0. I'd like for the solutions to be posted using purely real numbers. Instead, I get something like this:

{{x -> -(1/3) + 25/(3 (1/2 (-101 + 3 I Sqrt[5811]))^(1/3)) +
1/3 (1/2 (-101 + 3 I Sqrt[5811]))^(1/3)}, {x -> -(1/3) -
1/6 (1 + I Sqrt[3]) (1/2 (-101 + 3 I Sqrt[5811]))^(1/3) - (
25 (1 - I Sqrt[3]))/(
3 2^(2/3) (-101 + 3 I Sqrt[5811])^(1/3))}, {x -> -(1/3) -
1/6 (1 - I Sqrt[3]) (1/2 (-101 + 3 I Sqrt[5811]))^(1/3) - (
25 (1 + I Sqrt[3]))/(3 2^(2/3) (-101 + 3 I Sqrt[5811])^(1/3))}}

What commands would simplify this down to real numbers, if at all possible?

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Subject (listing for 'Solving Polynomials')
Author Date Posted
Solving Polynomials Nick 09/19/09 4:58pm
Re: Solving Polynomials TomD 09/21/09 6:32pm
Re: Solving Polynomials yehuda ben-s... 09/22/09 08:31am
Re: Solving Polynomials Peter Pein 09/25/09 5:41pm
Re: Solving Polynomials Peter Pein 09/25/09 5:48pm
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