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Límite de la función sinh(pi/n)/sinh(pi/(1+n))

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

tal que el límite para el numerador es
$$\lim_{n \to \infty} \frac{1}{\sinh{\left(\frac{\pi}{n + 1} \right)}} = \infty$$
y el límite para el denominador es
$$\lim_{n \to \infty} \frac{1}{\sinh{\left(\frac{\pi}{n} \right)}} = \infty$$
Vamos a probar las derivadas del numerador y denominador hasta eliminar la indeterminación.
$$\lim_{n \to \infty}\left(\frac{\sinh{\left(\frac{\pi}{n} \right)}}{\sinh{\left(\frac{\pi}{n + 1} \right)}}\right)$$
=
$$\lim_{n \to \infty}\left(\frac{\frac{d}{d n} \frac{1}{\sinh{\left(\frac{\pi}{n + 1} \right)}}}{\frac{d}{d n} \frac{1}{\sinh{\left(\frac{\pi}{n} \right)}}}\right)$$
=
$$\lim_{n \to \infty}\left(\frac{n^{2} \sinh^{2}{\left(\frac{\pi}{n} \right)} \cosh{\left(\frac{\pi}{n + 1} \right)}}{\left(n + 1\right)^{2} \sinh^{2}{\left(\frac{\pi}{n + 1} \right)} \cosh{\left(\frac{\pi}{n} \right)}}\right)$$
=
$$\lim_{n \to \infty}\left(\frac{1}{\left(\frac{1}{\sinh^{2}{\left(\frac{\pi}{n} \right)}} + \frac{2}{n \sinh^{2}{\left(\frac{\pi}{n} \right)}} + \frac{1}{n^{2} \sinh^{2}{\left(\frac{\pi}{n} \right)}}\right) \sinh^{2}{\left(\frac{\pi}{n + 1} \right)}}\right)$$
=
$$\lim_{n \to \infty}\left(\frac{\frac{d}{d n} \frac{1}{\sinh^{2}{\left(\frac{\pi}{n + 1} \right)}}}{\frac{d}{d n} \left(\frac{1}{\sinh^{2}{\left(\frac{\pi}{n} \right)}} + \frac{2}{n \sinh^{2}{\left(\frac{\pi}{n} \right)}} + \frac{1}{n^{2} \sinh^{2}{\left(\frac{\pi}{n} \right)}}\right)}\right)$$
=
$$\lim_{n \to \infty}\left(\frac{2 \pi \cosh{\left(\frac{\pi}{n + 1} \right)}}{\left(n + 1\right)^{2} \left(- \frac{2}{n^{2} \sinh^{2}{\left(\frac{\pi}{n} \right)}} + \frac{2 \pi \cosh{\left(\frac{\pi}{n} \right)}}{n^{2} \sinh^{3}{\left(\frac{\pi}{n} \right)}} - \frac{2}{n^{3} \sinh^{2}{\left(\frac{\pi}{n} \right)}} + \frac{4 \pi \cosh{\left(\frac{\pi}{n} \right)}}{n^{3} \sinh^{3}{\left(\frac{\pi}{n} \right)}} + \frac{2 \pi \cosh{\left(\frac{\pi}{n} \right)}}{n^{4} \sinh^{3}{\left(\frac{\pi}{n} \right)}}\right) \sinh^{3}{\left(\frac{\pi}{n + 1} \right)}}\right)$$
=
$$\lim_{n \to \infty}\left(\frac{2 \pi}{\left(n + 1\right)^{2} \left(- \frac{2}{n^{2} \sinh^{2}{\left(\frac{\pi}{n} \right)}} + \frac{2 \pi \cosh{\left(\frac{\pi}{n} \right)}}{n^{2} \sinh^{3}{\left(\frac{\pi}{n} \right)}} - \frac{2}{n^{3} \sinh^{2}{\left(\frac{\pi}{n} \right)}} + \frac{4 \pi \cosh{\left(\frac{\pi}{n} \right)}}{n^{3} \sinh^{3}{\left(\frac{\pi}{n} \right)}} + \frac{2 \pi \cosh{\left(\frac{\pi}{n} \right)}}{n^{4} \sinh^{3}{\left(\frac{\pi}{n} \right)}}\right) \sinh^{3}{\left(\frac{\pi}{n + 1} \right)}}\right)$$
=
$$\lim_{n \to \infty}\left(\frac{2 \pi}{\left(n + 1\right)^{2} \left(- \frac{2}{n^{2} \sinh^{2}{\left(\frac{\pi}{n} \right)}} + \frac{2 \pi \cosh{\left(\frac{\pi}{n} \right)}}{n^{2} \sinh^{3}{\left(\frac{\pi}{n} \right)}} - \frac{2}{n^{3} \sinh^{2}{\left(\frac{\pi}{n} \right)}} + \frac{4 \pi \cosh{\left(\frac{\pi}{n} \right)}}{n^{3} \sinh^{3}{\left(\frac{\pi}{n} \right)}} + \frac{2 \pi \cosh{\left(\frac{\pi}{n} \right)}}{n^{4} \sinh^{3}{\left(\frac{\pi}{n} \right)}}\right) \sinh^{3}{\left(\frac{\pi}{n + 1} \right)}}\right)$$
=
$$1$$
Como puedes ver, hemos aplicado el método de l'Hopital (utilizando la derivada del numerador y denominador) 2 vez (veces)
Gráfica
Respuesta rápida [src]
1
$$1$$
Otros límites con n→0, -oo, +oo, 1
$$\lim_{n \to \infty}\left(\frac{\sinh{\left(\frac{\pi}{n} \right)}}{\sinh{\left(\frac{\pi}{n + 1} \right)}}\right) = 1$$
$$\lim_{n \to 0^-}\left(\frac{\sinh{\left(\frac{\pi}{n} \right)}}{\sinh{\left(\frac{\pi}{n + 1} \right)}}\right) = -\infty$$
Más detalles con n→0 a la izquierda
$$\lim_{n \to 0^+}\left(\frac{\sinh{\left(\frac{\pi}{n} \right)}}{\sinh{\left(\frac{\pi}{n + 1} \right)}}\right) = \infty$$
Más detalles con n→0 a la derecha
$$\lim_{n \to 1^-}\left(\frac{\sinh{\left(\frac{\pi}{n} \right)}}{\sinh{\left(\frac{\pi}{n + 1} \right)}}\right) = \frac{-1 + e^{2 \pi}}{- e^{\frac{\pi}{2}} + e^{\frac{3 \pi}{2}}}$$
Más detalles con n→1 a la izquierda
$$\lim_{n \to 1^+}\left(\frac{\sinh{\left(\frac{\pi}{n} \right)}}{\sinh{\left(\frac{\pi}{n + 1} \right)}}\right) = \frac{-1 + e^{2 \pi}}{- e^{\frac{\pi}{2}} + e^{\frac{3 \pi}{2}}}$$
Más detalles con n→1 a la derecha
$$\lim_{n \to -\infty}\left(\frac{\sinh{\left(\frac{\pi}{n} \right)}}{\sinh{\left(\frac{\pi}{n + 1} \right)}}\right) = 1$$
Más detalles con n→-oo