Let f(x) = x^x
If we'll put x
= 1 => f(1) = 1^1 =1
We'll re-write the function
whose limit has to be found out:
lim (f(x) - 1)/(x -
1)
By definition, the derivative of a function f(x), at the
point x = 1 is: lim (f(x) - 1)/(x - 1) = f'(1).
We'll have
to determine the expression of the 1st derivative of
f(x).
We'll take natural logarithms both
sides:
ln f(x) = ln (x^x)
ln
f(x) = x*ln x
We'll differentiate with respect to x both
sides:
f'(x)/f(x) = ln x +
x/x
f'(x)/f(x) = ln x +
1
f'(x) = f(x)*(ln x +
1)
f'(x) = (x^x)*(ln x +
1)
Now, we'll replace x by
1:
f'(1) = 1*(ln 1 + 1)
f'(1)
= 1
Therefore, the limit of the function,
when x approaches to 1, is lim (x^x - 1)/(x - 1) =
1.
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