Description: Lemma for binomcxp . When C is not a nonnegative integer, the generalized sum in binomcxplemnn0 —which we will call P —is a convergent power series: its base b is always of smaller absolute value than the radius of convergence.
pserdv2 gives the derivative of P , which by dvradcnv also converges in that radius. When A is fixed at one, ( A + b ) times that derivative equals ( C x. P ) and fraction ( P / ( ( A + b ) ^c C ) ) is always defined with derivative zero, so the fraction is a constant—specifically one, because ( ( 1 + 0 ) ^c C ) = 1 . Thus ( ( 1 + b ) ^c C ) = ( Pb ) .
Finally, let b be ( B / A ) , and multiply both the binomial ( ( 1 + ( B / A ) ) ^c C ) and the sum ( P( B / A ) ) by ( A ^c C ) to get the result. (Contributed by Steve Rodriguez, 22-Apr-2020)
Ref | Expression | ||
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Hypotheses | binomcxp.a | |
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binomcxp.b | |
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binomcxp.lt | |
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binomcxp.c | |
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binomcxplem.f | |
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binomcxplem.s | |
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binomcxplem.r | |
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binomcxplem.e | |
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binomcxplem.d | |
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binomcxplem.p | |
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Assertion | binomcxplemnotnn0 | |