Chipset3600
- 79
- 0
Hello MHB, i can't hv success with this limit, help me please:
\lim_{x->2}\frac{5^{x}-25}{x-2}
\lim_{x->2}\frac{5^{x}-25}{x-2}
Chipset3600 said:Hello MHB, i can't hv success with this limit, help me please:
\lim_{x->2}\frac{5^{x}-25}{x-2}
chisigma said:Setting $x-2=y$ You obtain...
$\displaystyle \frac{5^{x}-25}{x-2} = \frac{5^{2+y}-5^{2}}{y}= 5^{2}\ \frac{5^{y}-1}{y} = 5^{2}\ \ln 5\ \frac{e^{y\ \ln 5} -1} {y\ \ln 5}$ (1)
and setting $z= y\ \ln 5$ You arrive at the limit...
$\displaystyle \lim_{z \rightarrow 0} 5^{2}\ \ln 5\ \frac{e^{z}-1}{z}$ (2)
... who contains a 'fundamental limit'...
Kind regards
$\chi$ $\sigma$
Chipset3600 said:I can't understood ur z=yln(5)
chisigma said:Simply You set $y\ \ln 5 = z$ and then insert z in (1)...
Kind regards
$\chi$ $\sigma$
Chipset3600 said:where it came from this ln(5)?
chisigma said:Is $\displaystyle 5^{y}= e^{y\ \ln 5}$...
Kind regards
$\chi$ $\sigma$