- #1
mpx86
- 10
- 0
why does it work only when h tends to zero?
[itex]\hat{}\[\begin{array}{l}
f(x + h) = xf(x)\\
Ef(x) = xf(x)\\
E = x\\
\ln E = hD\\
\ln x = hD\\
f(x) = y\\
y\ln x = hDy\\
y\ln x = h\frac{{dy}}{{dx}}\\
\int {} \ln xdx = h\int {} dy/y\\
x\log x/e = h\ln y + \ln c\\
x\log x/e = h\ln y/C\\
(x/h)\ln x/e = \ln y/C\\
C(x/e)\frac{{x/h}}{1} = y = f(x)\\
f(x + h) = C((x + h)/e)\frac{{(x + h)/h}}{1}\\
f(x + h)/f(x) = (((x + h)/e)\frac{{(x + h)/h}}{1})/(x/e)\frac{{x/h}}{1}\\
f(x + h)/f(x) = ((x + h)/x)\frac{{x/h}}{1})*((x + h)/e)\\
f(x + h)/f(x) = (1 + h/x)\frac{{x/h}}{1}*((x + h)/e)\\
\mathop {\lim }\limits_{h \to 0} f(x + h)/f(x) = \mathop {\lim }\limits_{h \to 0} e*((x + h)/e)\\
\mathop {\lim }\limits_{h \to 0} f(x + h)/f(x) = \mathop {\lim }\limits_{h \to 0} (x + h)\\
\mathop {\lim }\limits_{h \to 0} f(x + h)/f(x) = x\\
\\
\end{array}\][/itex]
[itex]\hat{}\[\begin{array}{l}
f(x + h) = xf(x)\\
Ef(x) = xf(x)\\
E = x\\
\ln E = hD\\
\ln x = hD\\
f(x) = y\\
y\ln x = hDy\\
y\ln x = h\frac{{dy}}{{dx}}\\
\int {} \ln xdx = h\int {} dy/y\\
x\log x/e = h\ln y + \ln c\\
x\log x/e = h\ln y/C\\
(x/h)\ln x/e = \ln y/C\\
C(x/e)\frac{{x/h}}{1} = y = f(x)\\
f(x + h) = C((x + h)/e)\frac{{(x + h)/h}}{1}\\
f(x + h)/f(x) = (((x + h)/e)\frac{{(x + h)/h}}{1})/(x/e)\frac{{x/h}}{1}\\
f(x + h)/f(x) = ((x + h)/x)\frac{{x/h}}{1})*((x + h)/e)\\
f(x + h)/f(x) = (1 + h/x)\frac{{x/h}}{1}*((x + h)/e)\\
\mathop {\lim }\limits_{h \to 0} f(x + h)/f(x) = \mathop {\lim }\limits_{h \to 0} e*((x + h)/e)\\
\mathop {\lim }\limits_{h \to 0} f(x + h)/f(x) = \mathop {\lim }\limits_{h \to 0} (x + h)\\
\mathop {\lim }\limits_{h \to 0} f(x + h)/f(x) = x\\
\\
\end{array}\][/itex]