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To: Lonesome in Massachussets
"Limit x -->0 [a^x] = 1 "

If a = 0 there's no inverse. Exponentiation is defined as the inverse of the natural log.

ax = exp(x/ln(a))

What's the ln of 0?

288 posted on 12/08/2006 6:01:57 PM PST by spunkets
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To: spunkets

You might want to check your algebra. (Your point is still valid. )

a^x = exp(x*log_e(a))...

try it...

>> x = randn;a=randn; a^x - exp(x*log(a))

ans =

0

(Matlab is perfectly happy with complex arithmetic. 'log' means 'log_e', 'log10' is log_10. Excel doesn't do complex arithmetic, but 'LOG' means 'LOG10', unless you enter a second argument, specifying the radix. 'LN' is 'log_e' to Excel. Excel also thinks that 1900 was leap year and 2100 wouldn't be, making them inconsistent with any known calendar, except the Excel calendar.)

The meaning of "Limit x -->0 [f(x)] = 1 " is that you can name any number you want, except zero, call it 'eta', no matter how small you make eta, I name a value of x, 'epsilon', such that a^epsilon < 1+eta and that as eta gets smaller, epislon also gets smaller.


310 posted on 12/09/2006 7:06:22 AM PST by Lonesome in Massachussets (The hallmark of a crackpot conspiracy theory is that it expands to include countervailing evidence.)
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