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Is there any simple way to get only the real solutions of the eq. x^3-1=x?

I've tried:


But it gives the complex ones, too.

I have Mathematica 5.2

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closed as off-topic by Mr.Wizard Aug 1 '14 at 0:31

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1 Answer 1

There is a third argument for Solve but you can use NSolve to get a numerical solution in the Reals:

 NSolve[x^3 - 1 == x, x, Reals]

{{x -> 1.32471796}}

OR Solve for exact Root solutions

Solve[x^3 - 1 == x, x, Reals]

{{x -> Root[-1 - #1 + #1^3 &, 1]}}

OR as Michael E2 noted in the comments, using ToRadicals will give you something more sensible.

Solve[x^3 - 1 == x, x, Reals] // ToRadicals

Mathematica graphics

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And ... // ToRadicals if desired. –  Michael E2 Aug 1 '14 at 1:30
@MichaelE2. Thanks, I'll add that. –  RunnyKine Aug 1 '14 at 1:35

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