Monday, 29 December 2014

real analysis - Find limxto0fracln(x2+1)x2 without L'hopital's rule



I have to find the limit without L'hopital's rule:
lim




Is it possible?
I thought about using squeeze theorem or something, but it didn't work out.



Hints are more than welcome!



P.S - I didn't study Taylor series or Integrals yet.


Answer



\begin{align} \lim_{x \to 0} \frac{\ln (x^2+1)} {x^2}&=\lim_{x \to 0} \ln (x^2+1)^{\frac{1}{x^2}}\\ &=\ln\left(\lim_{x \to 0} (x^2+1)^{\frac{1}{x^2}}\right)\\ &=\ln e=1 \end{align}


No comments:

Post a Comment

real analysis - How to find lim_{hrightarrow 0}frac{sin(ha)}{h}

How to find \lim_{h\rightarrow 0}\frac{\sin(ha)}{h} without lhopital rule? I know when I use lhopital I easy get $$ \lim_{h\rightarrow 0}...