Tuesday, 20 January 2015

calculus - I want to find limlimitsxto5frac2x25x5 without using l'Hopital's rule



I want to solve this limit without using L'Hopital's rule:
lim



And thanks.



Answer



You could do this as well. Write x = 5+h. So as x \to 5, h \to 0. Therefore the required limit is



\begin{align*} \lim_{h \to 0 } \frac{2^{5+h}-2^{5}}{h} &= 2^{5} \cdot \lim_{h \to 0}\Bigl[ \frac{2^{h}-1}{h}\Bigr] \\ &= 2^{5} \cdot M \end{align*}



where M= Some value in \log. I forgot the formula.



ADDED: The formula is \lim_{x \to 0} \frac{a^{x}-1}{x} = \log{a}



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}...