Sr Examen

Límite de la función cot(x)*log(log(e+x))

cuando
v

Para puntos concretos:

Gráfico:

interior superior

Definida a trozos:

Solución

Ha introducido [src]
 lim (cot(x)*log(log(E + x)))
x->0+                        
$$\lim_{x \to 0^+}\left(\log{\left(\log{\left(x + e \right)} \right)} \cot{\left(x \right)}\right)$$
Limit(cot(x)*log(log(E + x)), x, 0)
Método de l'Hopital
Tenemos la indeterminación de tipo
0/0,

tal que el límite para el numerador es
$$\lim_{x \to 0^+} \log{\left(\log{\left(x + e \right)} \right)} = 0$$
y el límite para el denominador es
$$\lim_{x \to 0^+} \frac{1}{\cot{\left(x \right)}} = 0$$
Vamos a probar las derivadas del numerador y denominador hasta eliminar la indeterminación.
$$\lim_{x \to 0^+}\left(\log{\left(\log{\left(x + e \right)} \right)} \cot{\left(x \right)}\right)$$
=
$$\lim_{x \to 0^+}\left(\frac{\frac{d}{d x} \log{\left(\log{\left(x + e \right)} \right)}}{\frac{d}{d x} \frac{1}{\cot{\left(x \right)}}}\right)$$
=
$$\lim_{x \to 0^+}\left(\frac{\cot^{2}{\left(x \right)}}{\left(x + e\right) \left(\cot^{2}{\left(x \right)} + 1\right) \log{\left(x + e \right)}}\right)$$
=
$$\lim_{x \to 0^+}\left(\frac{\cot^{2}{\left(x \right)}}{e \left(\cot^{2}{\left(x \right)} + 1\right)}\right)$$
=
$$\lim_{x \to 0^+}\left(\frac{\frac{d}{d x} \frac{1}{\cot^{2}{\left(x \right)} + 1}}{\frac{d}{d x} \frac{e}{\cot^{2}{\left(x \right)}}}\right)$$
=
$$\lim_{x \to 0^+}\left(\frac{1}{\left(2 \cot^{2}{\left(x \right)} + 2\right) \left(- \frac{e \cot^{4}{\left(x \right)}}{- 2 \cot^{6}{\left(x \right)} - 2 \cot^{4}{\left(x \right)}} - \frac{2 e \cot^{2}{\left(x \right)}}{- 2 \cot^{6}{\left(x \right)} - 2 \cot^{4}{\left(x \right)}} - \frac{e}{- 2 \cot^{6}{\left(x \right)} - 2 \cot^{4}{\left(x \right)}}\right)}\right)$$
=
$$\lim_{x \to 0^+}\left(\frac{\frac{d}{d x} \frac{1}{2 \cot^{2}{\left(x \right)} + 2}}{\frac{d}{d x} \left(- \frac{e \cot^{4}{\left(x \right)}}{- 2 \cot^{6}{\left(x \right)} - 2 \cot^{4}{\left(x \right)}} - \frac{2 e \cot^{2}{\left(x \right)}}{- 2 \cot^{6}{\left(x \right)} - 2 \cot^{4}{\left(x \right)}} - \frac{e}{- 2 \cot^{6}{\left(x \right)} - 2 \cot^{4}{\left(x \right)}}\right)}\right)$$
=
$$\lim_{x \to 0^+}\left(- \frac{2 \left(- 2 \cot^{2}{\left(x \right)} - 2\right) \cot{\left(x \right)}}{\left(2 \cot^{2}{\left(x \right)} + 2\right)^{2} \left(- \frac{e \left(2 \left(- 6 \cot^{2}{\left(x \right)} - 6\right) \cot^{5}{\left(x \right)} + 2 \left(- 4 \cot^{2}{\left(x \right)} - 4\right) \cot^{3}{\left(x \right)}\right) \cot^{4}{\left(x \right)}}{\left(- 2 \cot^{6}{\left(x \right)} - 2 \cot^{4}{\left(x \right)}\right)^{2}} - \frac{2 e \left(2 \left(- 6 \cot^{2}{\left(x \right)} - 6\right) \cot^{5}{\left(x \right)} + 2 \left(- 4 \cot^{2}{\left(x \right)} - 4\right) \cot^{3}{\left(x \right)}\right) \cot^{2}{\left(x \right)}}{\left(- 2 \cot^{6}{\left(x \right)} - 2 \cot^{4}{\left(x \right)}\right)^{2}} - \frac{e \left(2 \left(- 6 \cot^{2}{\left(x \right)} - 6\right) \cot^{5}{\left(x \right)} + 2 \left(- 4 \cot^{2}{\left(x \right)} - 4\right) \cot^{3}{\left(x \right)}\right)}{\left(- 2 \cot^{6}{\left(x \right)} - 2 \cot^{4}{\left(x \right)}\right)^{2}} - \frac{e \left(- 4 \cot^{2}{\left(x \right)} - 4\right) \cot^{3}{\left(x \right)}}{- 2 \cot^{6}{\left(x \right)} - 2 \cot^{4}{\left(x \right)}} - \frac{2 e \left(- 2 \cot^{2}{\left(x \right)} - 2\right) \cot{\left(x \right)}}{- 2 \cot^{6}{\left(x \right)} - 2 \cot^{4}{\left(x \right)}}\right)}\right)$$
=
$$\lim_{x \to 0^+}\left(- \frac{2 \left(- 2 \cot^{2}{\left(x \right)} - 2\right) \cot{\left(x \right)}}{\left(2 \cot^{2}{\left(x \right)} + 2\right)^{2} \left(- \frac{e \left(2 \left(- 6 \cot^{2}{\left(x \right)} - 6\right) \cot^{5}{\left(x \right)} + 2 \left(- 4 \cot^{2}{\left(x \right)} - 4\right) \cot^{3}{\left(x \right)}\right) \cot^{4}{\left(x \right)}}{\left(- 2 \cot^{6}{\left(x \right)} - 2 \cot^{4}{\left(x \right)}\right)^{2}} - \frac{2 e \left(2 \left(- 6 \cot^{2}{\left(x \right)} - 6\right) \cot^{5}{\left(x \right)} + 2 \left(- 4 \cot^{2}{\left(x \right)} - 4\right) \cot^{3}{\left(x \right)}\right) \cot^{2}{\left(x \right)}}{\left(- 2 \cot^{6}{\left(x \right)} - 2 \cot^{4}{\left(x \right)}\right)^{2}} - \frac{e \left(2 \left(- 6 \cot^{2}{\left(x \right)} - 6\right) \cot^{5}{\left(x \right)} + 2 \left(- 4 \cot^{2}{\left(x \right)} - 4\right) \cot^{3}{\left(x \right)}\right)}{\left(- 2 \cot^{6}{\left(x \right)} - 2 \cot^{4}{\left(x \right)}\right)^{2}} - \frac{e \left(- 4 \cot^{2}{\left(x \right)} - 4\right) \cot^{3}{\left(x \right)}}{- 2 \cot^{6}{\left(x \right)} - 2 \cot^{4}{\left(x \right)}} - \frac{2 e \left(- 2 \cot^{2}{\left(x \right)} - 2\right) \cot{\left(x \right)}}{- 2 \cot^{6}{\left(x \right)} - 2 \cot^{4}{\left(x \right)}}\right)}\right)$$
=
$$e^{-1}$$
Como puedes ver, hemos aplicado el método de l'Hopital (utilizando la derivada del numerador y denominador) 3 vez (veces)
Gráfica
Otros límites con x→0, -oo, +oo, 1
$$\lim_{x \to 0^-}\left(\log{\left(\log{\left(x + e \right)} \right)} \cot{\left(x \right)}\right) = e^{-1}$$
Más detalles con x→0 a la izquierda
$$\lim_{x \to 0^+}\left(\log{\left(\log{\left(x + e \right)} \right)} \cot{\left(x \right)}\right) = e^{-1}$$
$$\lim_{x \to \infty}\left(\log{\left(\log{\left(x + e \right)} \right)} \cot{\left(x \right)}\right)$$
Más detalles con x→oo
$$\lim_{x \to 1^-}\left(\log{\left(\log{\left(x + e \right)} \right)} \cot{\left(x \right)}\right) = \frac{\log{\left(\log{\left(1 + e \right)} \right)}}{\tan{\left(1 \right)}}$$
Más detalles con x→1 a la izquierda
$$\lim_{x \to 1^+}\left(\log{\left(\log{\left(x + e \right)} \right)} \cot{\left(x \right)}\right) = \frac{\log{\left(\log{\left(1 + e \right)} \right)}}{\tan{\left(1 \right)}}$$
Más detalles con x→1 a la derecha
$$\lim_{x \to -\infty}\left(\log{\left(\log{\left(x + e \right)} \right)} \cot{\left(x \right)}\right)$$
Más detalles con x→-oo
Respuesta rápida [src]
 -1
e  
$$e^{-1}$$
A la izquierda y a la derecha [src]
 lim (cot(x)*log(log(E + x)))
x->0+                        
$$\lim_{x \to 0^+}\left(\log{\left(\log{\left(x + e \right)} \right)} \cot{\left(x \right)}\right)$$
 -1
e  
$$e^{-1}$$
= 0.367879441171442
 lim (cot(x)*log(log(E + x)))
x->0-                        
$$\lim_{x \to 0^-}\left(\log{\left(\log{\left(x + e \right)} \right)} \cot{\left(x \right)}\right)$$
 -1
e  
$$e^{-1}$$
= 0.367879441171442
= 0.367879441171442
Respuesta numérica [src]
0.367879441171442
0.367879441171442