Description: Lemma for vieta1 : inductive step. Let z be a root of F . Then F = ( Xp - z ) x. Q for some Q by the factor theorem, and Q is a degree- D polynomial, so by the induction hypothesis sum_ x e. (`' Q " 0 ) x = -u ( coeff `Q )( D - 1 ) / ( coeffQ )D , so sum_ x e. R x = z - ( coeffQ )` ` ( D - 1 ) / ( coeffQ )D . Now the coefficients of F are A( D + 1 ) = ( coeffQ )D and AD = sum_ k e. ( 0 ... D ) ( coeffXp - z )k x. ( coeffQ ) ` `( D - k ) , which works out to -u z x. ( coeffQ )D + ( coeffQ )( D - 1 ) , so putting it all together we have sum_ x e. R x = -u AD / A( D + 1 ) as we wanted to show. (Contributed by Mario Carneiro, 28-Jul-2014)
Ref | Expression | ||
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Hypotheses | vieta1.1 | |
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vieta1.2 | |
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vieta1.3 | |
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vieta1.4 | |
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vieta1.5 | |
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vieta1lem.6 | |
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vieta1lem.7 | |
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vieta1lem.8 | |
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vieta1lem.9 | |
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Assertion | vieta1lem2 | |