El gráfico de la función cruce el eje X con f = 0
o sea hay que resolver la ecuación:
$$\log{\left(\cos{\left(\sqrt{x} \right)} \right)} = 0$$
Resolvermos esta ecuaciónPuntos de cruce con el eje X:
Solución analítica$$x_{1} = 0$$
$$x_{2} = 4 \pi^{2}$$
Solución numérica$$x_{1} = 39.4784196931281$$
$$x_{2} = 39.4784062959722$$
$$x_{3} = 39.4784103413578$$
$$x_{4} = 0$$
$$x_{5} = 39.4784244809486$$
$$x_{6} = 39.4784254541406$$
$$x_{7} = 39.4784188022266$$
$$x_{8} = 39.4784159867671$$
$$x_{9} = 39.4784134938697$$
$$x_{10} = 39.4784179014877$$
$$x_{11} = 39.4784054103828$$
$$x_{12} = 39.4784119202347$$
$$x_{13} = 39.4784122864094$$
$$x_{14} = 39.4784005773107$$
$$x_{15} = 39.4784279368965$$
$$x_{16} = 39.4784216040526$$
$$x_{17} = 39.4784169897246$$
$$x_{18} = 39.4784135502088$$
$$x_{19} = 39.4784219268824$$
$$x_{20} = 39.4784064029087$$
$$x_{21} = 39.47842522874$$
$$x_{22} = 39.4784232400798$$
$$x_{23} = 39.4784227155226$$
$$x_{24} = 39.4784206139581$$
$$x_{25} = 39.478414864914$$
$$x_{26} = 39.4784202473119$$
$$x_{27} = 39.4784183157447$$
$$x_{28} = 39.4784097343173$$
$$x_{29} = 39.4784198232879$$
$$x_{30} = 39.4783997423329$$
$$x_{31} = 39.4784233518974$$
$$x_{32} = 39.4784233026603$$
$$x_{33} = 39.4784249348881$$
$$x_{34} = 39.4784315267865$$
$$x_{35} = 39.4784256755471$$
$$x_{36} = 39.4784237672926$$
$$x_{37} = 39.4784160944136$$
$$x_{38} = 39.4784240272617$$