What does exponential growth really mean?

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Discussion Overview

The discussion revolves around the concept of exponential growth, exploring its definitions and implications in various contexts. Participants examine different mathematical representations and interpretations of exponential growth, including the specific forms of functions like e^x and a^x.

Discussion Character

  • Technical explanation, Conceptual clarification, Debate/contested

Main Points Raised

  • One participant suggests that exponential growth is often equated with e^x, but questions why doubling (2^x) is also considered exponential growth.
  • Another participant asserts that any number raised to a positive variable power qualifies as exponential growth, emphasizing the relationship between growth rate and the current quantity.
  • A different viewpoint clarifies that exponential growth can be expressed as e^{kx} for any constant k, noting the equivalence of a^x to exponential growth through logarithmic transformation.
  • One participant provides a definition of exponential growth as a growth rate that is proportional to the current value, using population growth as an example.

Areas of Agreement / Disagreement

Participants express differing views on the definition and representation of exponential growth, indicating that multiple competing interpretations exist without a clear consensus.

Contextual Notes

Participants reference various mathematical forms and definitions, but the discussion does not resolve the nuances of these interpretations or their implications in different contexts.

jaydnul
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I've always thought that when people say exponential growth, they mean e^x.

But other times I hear people just say that the quantity doubles 2^x every time.

So which is it? And if it's just doubling, why don't we say that 3^x or 4^x is exponential growth as well, since that's what those functions are technically called?

Thanks
 
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Any number raised to a positive variable power is exponential growth. The rules of logs and exponents can be used to convert one equation A^x to any other equivalent aB^x.

Exponential growth means the rate of growth of a quantity is proportional to the amount currently present.
 
Exponential growth means e^{kx} for any constant k. But<br /> a^x = e^{x \log_e a}<br />so a^x is also exponential growth for any constant a.
 
Another (identical) way to define exponential growth is a growth rate proportional to the current value. The classic example is population.
#dp/dt = rp#
 

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