Hallemos los puntos de flexiones, para eso hay que resolver la ecuación
$$\frac{d^{2}}{d x^{2}} f{\left(x \right)} = 0$$
(la segunda derivada es igual a cero),
las raíces de la ecuación obtenida serán los puntos de flexión para el gráfico de la función indicado:
$$\frac{d^{2}}{d x^{2}} f{\left(x \right)} = $$
segunda derivada$$\frac{- \left(\frac{\log{\left(x \right)} + 1}{x \log{\left(x \right)} - 3} + \frac{1}{x}\right) \left(x \left(\log{\left(x \right)} + 1\right) + x \log{\left(x \right)} - 3\right) + 2 \log{\left(x \right)} + 3 - \frac{\left(\log{\left(x \right)} + 1\right) \left(x \left(\log{\left(x \right)} + 1\right) + x \log{\left(x \right)} - 3\right)}{x \log{\left(x \right)} - 3} - \frac{x \left(\log{\left(x \right)} + 1\right) + x \log{\left(x \right)} - 3}{x}}{x^{2} \left(x \log{\left(x \right)} - 3\right)^{2}} = 0$$
Resolvermos esta ecuaciónRaíces de esta ecuación
$$x_{1} = 2219.83784068695$$
$$x_{2} = 4996.71253818685$$
$$x_{3} = 1488.23478683043$$
$$x_{4} = 7806.32703231882$$
$$x_{5} = 7994.42222252872$$
$$x_{6} = 3325.20899543897$$
$$x_{7} = 8936.10167154033$$
$$x_{8} = 4438.0670150755$$
$$x_{9} = 3695.43445350704$$
$$x_{10} = 8747.61199809409$$
$$x_{11} = 6304.84882748263$$
$$x_{12} = 1124.05134377679$$
$$x_{13} = 5743.49207902446$$
$$x_{14} = 2771.44437763248$$
$$x_{15} = 7242.56250687175$$
$$x_{16} = 6492.18863709021$$
$$x_{17} = 5183.21230596183$$
$$x_{18} = 2036.50471071084$$
$$x_{19} = 9124.66453061611$$
$$x_{20} = 7618.31708975316$$
$$x_{21} = 4252.15637608135$$
$$x_{22} = 942.144366779401$$
$$x_{23} = 1670.70159905966$$
$$x_{24} = 8559.19730164921$$
$$x_{25} = 5556.60681785561$$
$$x_{26} = 2403.44675825308$$
$$x_{27} = 7054.82295237432$$
$$x_{28} = 4810.35128158043$$
$$x_{29} = 4624.13411656892$$
$$x_{30} = 3140.40048888017$$
$$x_{31} = 3510.22358713837$$
$$x_{32} = 8182.60041139598$$
$$x_{33} = 5369.8453633436$$
$$x_{34} = 1306.03676349223$$
$$x_{35} = 7430.39475490943$$
$$x_{36} = 2587.31970701794$$
$$x_{37} = 1853.45734094122$$
$$x_{38} = 2955.80856130322$$
$$x_{39} = 3880.83244984758$$
$$x_{40} = 8370.85945376574$$
$$x_{41} = 6867.17883525318$$
$$x_{42} = 6679.63304679598$$
$$x_{43} = 4066.40906404448$$
$$x_{44} = 5930.49683380091$$
$$x_{45} = 6117.6170242757$$
Además hay que calcular los límites de y'' para los argumentos tendientes a los puntos de indeterminación de la función:
Puntos donde hay indeterminación:
$$x_{1} = 0$$
$$x_{2} = 2.85739078351437$$
$$\lim_{x \to 0^-}\left(\frac{- \left(\frac{\log{\left(x \right)} + 1}{x \log{\left(x \right)} - 3} + \frac{1}{x}\right) \left(x \left(\log{\left(x \right)} + 1\right) + x \log{\left(x \right)} - 3\right) + 2 \log{\left(x \right)} + 3 - \frac{\left(\log{\left(x \right)} + 1\right) \left(x \left(\log{\left(x \right)} + 1\right) + x \log{\left(x \right)} - 3\right)}{x \log{\left(x \right)} - 3} - \frac{x \left(\log{\left(x \right)} + 1\right) + x \log{\left(x \right)} - 3}{x}}{x^{2} \left(x \log{\left(x \right)} - 3\right)^{2}}\right) = -\infty$$
$$\lim_{x \to 0^+}\left(\frac{- \left(\frac{\log{\left(x \right)} + 1}{x \log{\left(x \right)} - 3} + \frac{1}{x}\right) \left(x \left(\log{\left(x \right)} + 1\right) + x \log{\left(x \right)} - 3\right) + 2 \log{\left(x \right)} + 3 - \frac{\left(\log{\left(x \right)} + 1\right) \left(x \left(\log{\left(x \right)} + 1\right) + x \log{\left(x \right)} - 3\right)}{x \log{\left(x \right)} - 3} - \frac{x \left(\log{\left(x \right)} + 1\right) + x \log{\left(x \right)} - 3}{x}}{x^{2} \left(x \log{\left(x \right)} - 3\right)^{2}}\right) = \infty$$
- los límites no son iguales, signo
$$x_{1} = 0$$
- es el punto de flexión
$$\lim_{x \to 2.85739078351437^-}\left(\frac{- \left(\frac{\log{\left(x \right)} + 1}{x \log{\left(x \right)} - 3} + \frac{1}{x}\right) \left(x \left(\log{\left(x \right)} + 1\right) + x \log{\left(x \right)} - 3\right) + 2 \log{\left(x \right)} + 3 - \frac{\left(\log{\left(x \right)} + 1\right) \left(x \left(\log{\left(x \right)} + 1\right) + x \log{\left(x \right)} - 3\right)}{x \log{\left(x \right)} - 3} - \frac{x \left(\log{\left(x \right)} + 1\right) + x \log{\left(x \right)} - 3}{x}}{x^{2} \left(x \log{\left(x \right)} - 3\right)^{2}}\right) = 3.35829476558303 \cdot 10^{46}$$
$$\lim_{x \to 2.85739078351437^+}\left(\frac{- \left(\frac{\log{\left(x \right)} + 1}{x \log{\left(x \right)} - 3} + \frac{1}{x}\right) \left(x \left(\log{\left(x \right)} + 1\right) + x \log{\left(x \right)} - 3\right) + 2 \log{\left(x \right)} + 3 - \frac{\left(\log{\left(x \right)} + 1\right) \left(x \left(\log{\left(x \right)} + 1\right) + x \log{\left(x \right)} - 3\right)}{x \log{\left(x \right)} - 3} - \frac{x \left(\log{\left(x \right)} + 1\right) + x \log{\left(x \right)} - 3}{x}}{x^{2} \left(x \log{\left(x \right)} - 3\right)^{2}}\right) = 3.35829476558303 \cdot 10^{46}$$
- los límites son iguales, es decir omitimos el punto correspondiente
Intervalos de convexidad y concavidad:Hallemos los intervales donde la función es convexa o cóncava, para eso veamos cómo se comporta la función en los puntos de flexiones:
No tiene corvaduras en todo el eje numérico