Sr Examen

Límite de la función log(sin(x))*tan(x)

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Solución

Ha introducido [src]
 lim (log(sin(x))*tan(x))
x->0+                    
limx0+(log(sin(x))tan(x))\lim_{x \to 0^+}\left(\log{\left(\sin{\left(x \right)} \right)} \tan{\left(x \right)}\right)
Limit(log(sin(x))*tan(x), x, 0)
Método de l'Hopital
Tenemos la indeterminación de tipo
0/0,

tal que el límite para el numerador es
limx0+tan(x)=0\lim_{x \to 0^+} \tan{\left(x \right)} = 0
y el límite para el denominador es
limx0+1log(sin(x))=0\lim_{x \to 0^+} \frac{1}{\log{\left(\sin{\left(x \right)} \right)}} = 0
Vamos a probar las derivadas del numerador y denominador hasta eliminar la indeterminación.
limx0+(log(sin(x))tan(x))\lim_{x \to 0^+}\left(\log{\left(\sin{\left(x \right)} \right)} \tan{\left(x \right)}\right)
=
limx0+(ddxtan(x)ddx1log(sin(x)))\lim_{x \to 0^+}\left(\frac{\frac{d}{d x} \tan{\left(x \right)}}{\frac{d}{d x} \frac{1}{\log{\left(\sin{\left(x \right)} \right)}}}\right)
=
limx0+((tan2(x)+1)log(sin(x))2sin(x)cos(x))\lim_{x \to 0^+}\left(- \frac{\left(\tan^{2}{\left(x \right)} + 1\right) \log{\left(\sin{\left(x \right)} \right)}^{2} \sin{\left(x \right)}}{\cos{\left(x \right)}}\right)
=
limx0+((tan2(x)+1)log(sin(x))2sin(x))\lim_{x \to 0^+}\left(- \left(\tan^{2}{\left(x \right)} + 1\right) \log{\left(\sin{\left(x \right)} \right)}^{2} \sin{\left(x \right)}\right)
=
limx0+(ddx(log(sin(x))2sin(x))ddx1tan2(x)+1)\lim_{x \to 0^+}\left(\frac{\frac{d}{d x} \left(- \log{\left(\sin{\left(x \right)} \right)}^{2} \sin{\left(x \right)}\right)}{\frac{d}{d x} \frac{1}{\tan^{2}{\left(x \right)} + 1}}\right)
=
limx0+((log(sin(x))2cos(x)2log(sin(x))cos(x))(tan2(x)+1)2(2tan2(x)+2)tan(x))\lim_{x \to 0^+}\left(- \frac{\left(- \log{\left(\sin{\left(x \right)} \right)}^{2} \cos{\left(x \right)} - 2 \log{\left(\sin{\left(x \right)} \right)} \cos{\left(x \right)}\right) \left(\tan^{2}{\left(x \right)} + 1\right)^{2}}{\left(2 \tan^{2}{\left(x \right)} + 2\right) \tan{\left(x \right)}}\right)
=
limx0+(log(sin(x))2cos(x)2log(sin(x))cos(x)2tan(x))\lim_{x \to 0^+}\left(- \frac{- \log{\left(\sin{\left(x \right)} \right)}^{2} \cos{\left(x \right)} - 2 \log{\left(\sin{\left(x \right)} \right)} \cos{\left(x \right)}}{2 \tan{\left(x \right)}}\right)
=
limx0+(log(sin(x))2cos(x)2log(sin(x))cos(x)2tan(x))\lim_{x \to 0^+}\left(- \frac{- \log{\left(\sin{\left(x \right)} \right)}^{2} \cos{\left(x \right)} - 2 \log{\left(\sin{\left(x \right)} \right)} \cos{\left(x \right)}}{2 \tan{\left(x \right)}}\right)
=
00
Como puedes ver, hemos aplicado el método de l'Hopital (utilizando la derivada del numerador y denominador) 2 vez (veces)
Gráfica
02468-8-6-4-2-10101.0-1.0
Otros límites con x→0, -oo, +oo, 1
limx0(log(sin(x))tan(x))=0\lim_{x \to 0^-}\left(\log{\left(\sin{\left(x \right)} \right)} \tan{\left(x \right)}\right) = 0
Más detalles con x→0 a la izquierda
limx0+(log(sin(x))tan(x))=0\lim_{x \to 0^+}\left(\log{\left(\sin{\left(x \right)} \right)} \tan{\left(x \right)}\right) = 0
limx(log(sin(x))tan(x))\lim_{x \to \infty}\left(\log{\left(\sin{\left(x \right)} \right)} \tan{\left(x \right)}\right)
Más detalles con x→oo
limx1(log(sin(x))tan(x))=log(sin(1))tan(1)\lim_{x \to 1^-}\left(\log{\left(\sin{\left(x \right)} \right)} \tan{\left(x \right)}\right) = \log{\left(\sin{\left(1 \right)} \right)} \tan{\left(1 \right)}
Más detalles con x→1 a la izquierda
limx1+(log(sin(x))tan(x))=log(sin(1))tan(1)\lim_{x \to 1^+}\left(\log{\left(\sin{\left(x \right)} \right)} \tan{\left(x \right)}\right) = \log{\left(\sin{\left(1 \right)} \right)} \tan{\left(1 \right)}
Más detalles con x→1 a la derecha
limx(log(sin(x))tan(x))\lim_{x \to -\infty}\left(\log{\left(\sin{\left(x \right)} \right)} \tan{\left(x \right)}\right)
Más detalles con x→-oo
Respuesta rápida [src]
0
00
A la izquierda y a la derecha [src]
 lim (log(sin(x))*tan(x))
x->0+                    
limx0+(log(sin(x))tan(x))\lim_{x \to 0^+}\left(\log{\left(\sin{\left(x \right)} \right)} \tan{\left(x \right)}\right)
0
00
= -0.00189820965659739
 lim (log(sin(x))*tan(x))
x->0-                    
limx0(log(sin(x))tan(x))\lim_{x \to 0^-}\left(\log{\left(\sin{\left(x \right)} \right)} \tan{\left(x \right)}\right)
0
00
= (0.00187911434269187 - 0.000771396926340757j)
= (0.00187911434269187 - 0.000771396926340757j)
Respuesta numérica [src]
-0.00189820965659739
-0.00189820965659739
Gráfico
Límite de la función log(sin(x))*tan(x)