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What's your definition of exponential?

If I invest $1,000 at 5% annual return, I expect to have 1000 * (1.05)^n after n years. That fits my definition of exponential - time is an exponent in the formula.



It's really not a matter of interpretation. Geometric and exponential growth are well defined mathematical concepts.

Geometric functions can have exponents. This does not imply the function is exponential. These are very different things.

https://en.m.wikipedia.org/wiki/Exponential_growth


The page you cite gives the formula for exponential growth as:

  {\displaystyle x_{t}=x_{0}(1+r)^{t}}
Um, right, let me translate that into something that can display here:

  x(t) = x(0) * (1+r)^t
Well, if you look at the formula I gave for compound interest:

x(t) is the value at time t,

x(0) is the value at time 0, namely $1000,

(1+r) is 1.05,

and t = n, the number of years.

So, from your own cited article, how is that not exponential?

Or were you agreeing with me, and disagreeing with glitchc?


My quibble was about geometrics vs exponential, but beyond the mathematical distinction of discreteness, they are equivalent, so I stand corrected on that front.




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