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I think you just have to show that f and f' dont have any factors in common with F
 
I think you just have to show that f and f' dont have any factors in common with F
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-If anyone cares after the fact, you are excatly right on how to solve this problem, there are no common factors between f and its derivative. That will suffice bt thms.
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  Allen

Latest revision as of 17:46, 23 November 2008

I can show that -1 isn't a multiple root, but I don't think that's really answering the question. Can anyone elaborate?

I used Theorem 20.5. Let f = the polynomial in the question and take the derivative. Prove there is no common factor between f and f prime. I'm not sure if this is correct though.


right. that's what i was using, but can you tell me how you showed that they don't have common factors?


Well the derivative is $ F'(x)=x^7 $. the only factors of this are $ x $,$ x^2 $,$ x^3 $,$ x^4 $,$ x^5 $,& $ x^6 $.

Since F(x) has the +1, they can never share a common factor, right? Unless my derivative is wrong. I took it to be in $ Z_3 $, so the $ 21x^{20} $ term disappeared.

I got the same derivative by using mod 3.

I think you just have to show that f and f' dont have any factors in common with F

-If anyone cares after the fact, you are excatly right on how to solve this problem, there are no common factors between f and its derivative. That will suffice bt thms.

  Allen

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