Is the Limit of (1 + 1/b)^b as b Approaches Infinity Equal to e?

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Discussion Overview

The discussion centers around the limit of the expression (1 + 1/b)^b as b approaches infinity, specifically whether this limit equals e. Participants explore various mathematical interpretations, definitions, and implications of limits, infinity, and the nature of exponential functions.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested
  • Mathematical reasoning

Main Points Raised

  • One participant presents a function f(x) and claims that as b increases, it converges to e, leading to the conclusion that (1 + 1/b)^b approaches e.
  • Another participant argues against direct substitution of b with infinity, stating that it leads to undefined expressions and emphasizes the importance of limits in calculations.
  • A different participant clarifies the concept of limits, suggesting that the value of e is reached when the base approaches 1 in a limiting sense, rather than being exactly 1 raised to infinity.
  • Some participants discuss the implications of treating infinity as a regular number, warning that such approaches can yield nonsensical results.
  • There is a contention regarding the series 1/1! + 1/2! + 1/3!... and its convergence, with participants questioning the validity of arguments made about its limit.
  • One participant mentions that 1 raised to the power of infinity can yield multiple values, indicating that this expression is inherently undefined.
  • Discussions arise about the behavior of the exponential function near essential singularities, with references to the Weierstrass theorem and its implications for complex functions.
  • Participants engage in a technical exploration of the exponential function's properties, including its non-zero nature across the complex plane and the implications of essential singularities.

Areas of Agreement / Disagreement

Participants express differing views on the validity of substituting infinity directly into expressions, the nature of limits, and the behavior of exponential functions. There is no consensus on the correctness of the various claims made regarding the limit and the properties of the functions discussed.

Contextual Notes

Some arguments rely on specific interpretations of limits and the treatment of infinity, which may not be universally accepted. The discussion includes unresolved mathematical steps and varying definitions that affect the conclusions drawn.

  • #31


Hurkyl said:
But +\infty is an extended real number, and you do have

\lim_{x \to +\infty} f(x) = f(+\infty)

when f is continuous at +\infty.

But the function is defined as a real-valued function, I believe (meaning

implicitly so). It may or not be extendable continuously to the Riemann sphere,

but AFAIK, it was defined as a real-valued functiuon of a real variable.
 

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