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log(4+3*n)^2*(1+n)/(n*log(1+3*n)^2)

Límite de la función log(4+3*n)^2*(1+n)/(n*log(1+3*n)^2)

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Solución

Ha introducido [src]
     /   2                 \
     |log (4 + 3*n)*(1 + n)|
 lim |---------------------|
n->oo|        2            |
     \   n*log (1 + 3*n)   /
$$\lim_{n \to \infty}\left(\frac{\left(n + 1\right) \log{\left(3 n + 4 \right)}^{2}}{n \log{\left(3 n + 1 \right)}^{2}}\right)$$
Limit((log(4 + 3*n)^2*(1 + n))/((n*log(1 + 3*n)^2)), n, oo, dir='-')
Método de l'Hopital
Tenemos la indeterminación de tipo
oo/oo,

tal que el límite para el numerador es
$$\lim_{n \to \infty} \log{\left(3 n + 4 \right)}^{2} = \infty$$
y el límite para el denominador es
$$\lim_{n \to \infty}\left(\frac{n \log{\left(3 n + 1 \right)}^{2}}{n + 1}\right) = \infty$$
Vamos a probar las derivadas del numerador y denominador hasta eliminar la indeterminación.
$$\lim_{n \to \infty}\left(\frac{\left(n + 1\right) \log{\left(3 n + 4 \right)}^{2}}{n \log{\left(3 n + 1 \right)}^{2}}\right)$$
=
Introducimos una pequeña modificación de la función bajo el signo del límite
$$\lim_{n \to \infty}\left(\frac{\left(n + 1\right) \log{\left(3 n + 4 \right)}^{2}}{n \log{\left(3 n + 1 \right)}^{2}}\right)$$
=
$$\lim_{n \to \infty}\left(\frac{\frac{d}{d n} \log{\left(3 n + 4 \right)}^{2}}{\frac{d}{d n} \frac{n \log{\left(3 n + 1 \right)}^{2}}{n + 1}}\right)$$
=
$$\lim_{n \to \infty}\left(\frac{1}{\left(\frac{n}{2 \log{\left(3 n + 4 \right)}} + \frac{2}{3 \log{\left(3 n + 4 \right)}}\right) \left(\frac{6 n \log{\left(3 n + 1 \right)}}{3 n^{2} + 4 n + 1} - \frac{n \log{\left(3 n + 1 \right)}^{2}}{n^{2} + 2 n + 1} + \frac{\log{\left(3 n + 1 \right)}^{2}}{n + 1}\right)}\right)$$
=
$$\lim_{n \to \infty}\left(\frac{\frac{d}{d n} \frac{1}{\frac{6 n \log{\left(3 n + 1 \right)}}{3 n^{2} + 4 n + 1} - \frac{n \log{\left(3 n + 1 \right)}^{2}}{n^{2} + 2 n + 1} + \frac{\log{\left(3 n + 1 \right)}^{2}}{n + 1}}}{\frac{d}{d n} \left(\frac{n}{2 \log{\left(3 n + 4 \right)}} + \frac{2}{3 \log{\left(3 n + 4 \right)}}\right)}\right)$$
=
$$\lim_{n \to \infty}\left(\frac{- \frac{6 n \left(- 6 n - 4\right) \log{\left(3 n + 1 \right)}}{\left(3 n^{2} + 4 n + 1\right)^{2}} + \frac{n \left(- 2 n - 2\right) \log{\left(3 n + 1 \right)}^{2}}{\left(n^{2} + 2 n + 1\right)^{2}} - \frac{18 n}{\left(3 n + 1\right) \left(3 n^{2} + 4 n + 1\right)} + \frac{6 n \log{\left(3 n + 1 \right)}}{\left(3 n + 1\right) \left(n^{2} + 2 n + 1\right)} - \frac{6 \log{\left(3 n + 1 \right)}}{3 n^{2} + 4 n + 1} + \frac{\log{\left(3 n + 1 \right)}^{2}}{n^{2} + 2 n + 1} - \frac{6 \log{\left(3 n + 1 \right)}}{\left(n + 1\right) \left(3 n + 1\right)} + \frac{\log{\left(3 n + 1 \right)}^{2}}{\left(n + 1\right)^{2}}}{\left(- \frac{3 n}{2 \left(3 n + 4\right) \log{\left(3 n + 4 \right)}^{2}} + \frac{1}{2 \log{\left(3 n + 4 \right)}} - \frac{2}{\left(3 n + 4\right) \log{\left(3 n + 4 \right)}^{2}}\right) \left(\frac{6 n \log{\left(3 n + 1 \right)}}{3 n^{2} + 4 n + 1} - \frac{n \log{\left(3 n + 1 \right)}^{2}}{n^{2} + 2 n + 1} + \frac{\log{\left(3 n + 1 \right)}^{2}}{n + 1}\right)^{2}}\right)$$
=
$$\lim_{n \to \infty}\left(\frac{- \frac{6 n \left(- 6 n - 4\right) \log{\left(3 n + 1 \right)}}{\left(3 n^{2} + 4 n + 1\right)^{2}} + \frac{n \left(- 2 n - 2\right) \log{\left(3 n + 1 \right)}^{2}}{\left(n^{2} + 2 n + 1\right)^{2}} - \frac{18 n}{\left(3 n + 1\right) \left(3 n^{2} + 4 n + 1\right)} + \frac{6 n \log{\left(3 n + 1 \right)}}{\left(3 n + 1\right) \left(n^{2} + 2 n + 1\right)} - \frac{6 \log{\left(3 n + 1 \right)}}{3 n^{2} + 4 n + 1} + \frac{\log{\left(3 n + 1 \right)}^{2}}{n^{2} + 2 n + 1} - \frac{6 \log{\left(3 n + 1 \right)}}{\left(n + 1\right) \left(3 n + 1\right)} + \frac{\log{\left(3 n + 1 \right)}^{2}}{\left(n + 1\right)^{2}}}{\left(- \frac{3 n}{2 \left(3 n + 4\right) \log{\left(3 n + 4 \right)}^{2}} + \frac{1}{2 \log{\left(3 n + 4 \right)}} - \frac{2}{\left(3 n + 4\right) \log{\left(3 n + 4 \right)}^{2}}\right) \left(\frac{6 n \log{\left(3 n + 1 \right)}}{3 n^{2} + 4 n + 1} - \frac{n \log{\left(3 n + 1 \right)}^{2}}{n^{2} + 2 n + 1} + \frac{\log{\left(3 n + 1 \right)}^{2}}{n + 1}\right)^{2}}\right)$$
=
$$1$$
Como puedes ver, hemos aplicado el método de l'Hopital (utilizando la derivada del numerador y denominador) 2 vez (veces)
Gráfica
Otros límites con n→0, -oo, +oo, 1
$$\lim_{n \to \infty}\left(\frac{\left(n + 1\right) \log{\left(3 n + 4 \right)}^{2}}{n \log{\left(3 n + 1 \right)}^{2}}\right) = 1$$
$$\lim_{n \to 0^-}\left(\frac{\left(n + 1\right) \log{\left(3 n + 4 \right)}^{2}}{n \log{\left(3 n + 1 \right)}^{2}}\right) = -\infty$$
Más detalles con n→0 a la izquierda
$$\lim_{n \to 0^+}\left(\frac{\left(n + 1\right) \log{\left(3 n + 4 \right)}^{2}}{n \log{\left(3 n + 1 \right)}^{2}}\right) = \infty$$
Más detalles con n→0 a la derecha
$$\lim_{n \to 1^-}\left(\frac{\left(n + 1\right) \log{\left(3 n + 4 \right)}^{2}}{n \log{\left(3 n + 1 \right)}^{2}}\right) = \frac{\log{\left(7 \right)}^{2}}{2 \log{\left(2 \right)}^{2}}$$
Más detalles con n→1 a la izquierda
$$\lim_{n \to 1^+}\left(\frac{\left(n + 1\right) \log{\left(3 n + 4 \right)}^{2}}{n \log{\left(3 n + 1 \right)}^{2}}\right) = \frac{\log{\left(7 \right)}^{2}}{2 \log{\left(2 \right)}^{2}}$$
Más detalles con n→1 a la derecha
$$\lim_{n \to -\infty}\left(\frac{\left(n + 1\right) \log{\left(3 n + 4 \right)}^{2}}{n \log{\left(3 n + 1 \right)}^{2}}\right) = 1$$
Más detalles con n→-oo
Respuesta rápida [src]
1
$$1$$
Gráfico
Límite de la función log(4+3*n)^2*(1+n)/(n*log(1+3*n)^2)