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Repair the scaled Taylor-series argument to prove irrationality of e^r for integers r>1

Determine whether the Taylor-series-based approach that assumes e^r = p/q, scales the series by q!, and attempts to bound the remainder term B = sum_{n=q+1}^\infty q! r^n / n! via a geometric-series estimate can be modified to yield 0 < B < 1 for integers r > 1, thereby establishing a contradiction and proving that e^r is irrational without appealing to orthogonal polynomials.

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Background

The paper first adapts Fourier’s proof of the irrationality of e to attempt to prove the irrationality of er for a positive integer r by scaling the Taylor series by q! under the assumption er = p/q. This produces an integer part plus a remainder term B.

Bounding B with a geometric series works for r = 1 but fails for r > 1 because the bound becomes large for large q, and thus does not yield 0 < B < 1 needed for the contradiction. The author notes it is possible the argument could be repaired but does not know how, leaving the question open in this exposition.

References

It is quite possible that the above argument can be repaired, but I do not know how to do so.

A well-motivated proof that pi is irrational (2403.20140 - Chow, 29 Mar 2024) in Section “The irrationality of e^r”