L'hopital's rule, indeterminate forms

Panphobia
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Homework Statement



lim_{x -> \infty} \left( \frac{x}{x+1} \right) ^ {x}

The Attempt at a Solution



So I did e^whole statement with ln(x/(x+1))*x, after that I multiplied that expression by 1/x/1/x, then I go ln(x/(x+1)/1/x, I tried taking derivative of top and bottom but it doesn't help with finding an answer.
 
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Panphobia said:
So I did e^whole statement with ln(x/(x+1))*x, after that I multiplied that expression by 1/x/1/x, then I go ln(x/(x+1)/1/x, I tried taking derivative of top and bottom but it doesn't help with finding an answer.

It did for me. Try it again, maybe.
 
Panphobia said:

Homework Statement



lim_{x -> \infty} \left( \frac{x}{x+1} \right) ^ {x}

The Attempt at a Solution



So I did e^whole statement with ln(x/(x+1))*x, after that I multiplied that expression by 1/x/1/x, then I go ln(x/(x+1)/1/x, I tried taking derivative of top and bottom but it doesn't help with finding an answer.

I wouldn't e^ln(statement).I would write it as

##y= \displaystyle \lim_{x \to \infty} \left( \frac{x}{x+1} \right)^x##
##\ln{y}= \displaystyle \lim_{x \to \infty} \ln{\left[\left( \frac{x}{x+1} \right)^x\right]}##

Then you eventually solve for y. What do you get when you perform l'Hospital's rule? This is the correct procedure so far.
 
There are two things I don't understand about this problem. First, when finding the nth root of a number, there should in theory be n solutions. However, the formula produces n+1 roots. Here is how. The first root is simply ##\left(r\right)^{\left(\frac{1}{n}\right)}##. Then you multiply this first root by n additional expressions given by the formula, as you go through k=0,1,...n-1. So you end up with n+1 roots, which cannot be correct. Let me illustrate what I mean. For this...
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