To prove this remarkable limit, we'll prove that the limit
of ratio of 2 consecutive terms of the sequence (an) exists and it's value is
1.
lim a n+1/a n = lim
a^[1/(n+1)]/a^(1/n)
We'll use the quotient property of
exponentials that have matching bases:
lim
a^[1/(n+1)]/a^(1/n) = lim a^[1/(n+1) - (1/n)]
lim
a^[1/(n+1) - (1/n)] = lim a^[-1/n(n+1)]
We'll use the
property of negative power:
lim a^[-1/n(n+1)] = lim
1/a^[1/n(n+1)]
lim 1/a^[1/n(n+1)] = 1/a^lim
[1/n(n+1)]
lim [1/n(n+1)] = 1/+infinite =
0
1/a^lim [1/n(n+1)] = 1/a^0 = 1/1 =
1
The limit of the ratio a n+1/ a n exists and it is
1.
Therefore, the remarkable limit, if n
approaches +infinite, is: lim a^(1/n) = 1.
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