Sunday, 19 April 2015

calculus - Deconstructing 00












It is well known that 00 is an indeterminate form. One way to see that is noticing that



lim



yet,



\lim_{x\to0}\;x^0 = 1\quad.



What if we make both terms go to 0, that is, how much is




L = \lim_{x\to0^+}\;x^x\quad?



By taking x\in \langle 1/k\rangle_{k\in\mathbb{N*}}\,, I concluded that it equals \lim_{x\to\infty}\;x^{-1/x}, but that's not helpful.


Answer



This is, unfortunately, not very exciting. Rewrite x^x as e^{x\log x} and take that limit. One l'Hôpital later, you get 1.


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