El gráfico de la función cruce el eje X con f = 0
o sea hay que resolver la ecuación:
$$\frac{\cos^{2}{\left(x \right)}}{2 \left(\cos^{2}{\left(x \right)} + 1\right)} = 0$$
Resolvermos esta ecuaciónPuntos de cruce con el eje X:
Solución analítica$$x_{1} = \frac{\pi}{2}$$
$$x_{2} = \frac{3 \pi}{2}$$
Solución numérica$$x_{1} = 26.7035375938913$$
$$x_{2} = 17.2787595633899$$
$$x_{3} = 32.9867228941353$$
$$x_{4} = -98.9601684093104$$
$$x_{5} = -67.5442421564402$$
$$x_{6} = 76.969020040638$$
$$x_{7} = 29.8451303102952$$
$$x_{8} = -48.6946861222051$$
$$x_{9} = -36.1283154261993$$
$$x_{10} = -95.8185758684594$$
$$x_{11} = -1.57079642164044$$
$$x_{12} = -32.9867227489063$$
$$x_{13} = -45.5530935782908$$
$$x_{14} = 64.4026493142196$$
$$x_{15} = 98.9601686017849$$
$$x_{16} = -14.1371668471947$$
$$x_{17} = 61.2610566820223$$
$$x_{18} = 70.685834566047$$
$$x_{19} = 14.1371670871753$$
$$x_{20} = 89.5353907674826$$
$$x_{21} = 1.57079647069791$$
$$x_{22} = -95.8185759201621$$
$$x_{23} = 136.659279422688$$
$$x_{24} = 7.85398174549375$$
$$x_{25} = -42.4115006785877$$
$$x_{26} = -92.6769832504273$$
$$x_{27} = 86.3937976593223$$
$$x_{28} = -51.8362786914439$$
$$x_{29} = -61.2610568791177$$
$$x_{30} = 67.5442421935219$$
$$x_{31} = 83.2522052396831$$
$$x_{32} = -70.6858346859033$$
$$x_{33} = -4.71238899750462$$
$$x_{34} = -39.2699079506635$$
$$x_{35} = -89.5353907344725$$
$$x_{36} = 67.5442420093282$$
$$x_{37} = -10.9955741932579$$
$$x_{38} = 149.225651356968$$
$$x_{39} = -20.4203521038741$$
$$x_{40} = 20.4203521568611$$
$$x_{41} = -39.2699083053871$$
$$x_{42} = 48.6946859914123$$
$$x_{43} = -23.5619450000243$$
$$x_{44} = -54.9778713034237$$
$$x_{45} = -39.2699066302699$$
$$x_{46} = 86.3937978930783$$
$$x_{47} = 26.7035374169454$$
$$x_{48} = 51.8362788887955$$
$$x_{49} = -174.35839231001$$
$$x_{50} = -26.7035375593873$$
$$x_{51} = 80.1106131476371$$
$$x_{52} = -83.2522054526444$$
$$x_{53} = 39.2699081232466$$
$$x_{54} = -7.85398150586668$$
$$x_{55} = -86.3937978284268$$
$$x_{56} = -76.9690199513052$$
$$x_{57} = -111.526538625772$$
$$x_{58} = 36.1283155349742$$
$$x_{59} = -58.1194641200293$$
$$x_{60} = -80.1106125847763$$
$$x_{61} = 95.8185760453363$$
$$x_{62} = 4.71238884265206$$
$$x_{63} = -73.8274272808401$$
$$x_{64} = 73.8274274671408$$
$$x_{65} = -29.8451300998261$$
$$x_{66} = 58.1194645155376$$
$$x_{67} = 45.5530936194006$$
$$x_{68} = 23.5619444674042$$
$$x_{69} = -64.4026492534396$$
$$x_{70} = 92.6769831408439$$
$$x_{71} = 32.9867229214717$$
$$x_{72} = 7.85398173163416$$
$$x_{73} = -58.1194640053894$$
$$x_{74} = -76.9690198568601$$
$$x_{75} = 23.5619450451243$$
$$x_{76} = 54.977871480518$$
$$x_{77} = 42.4115007354808$$
$$x_{78} = -17.2787597314612$$
$$x_{79} = 10.9955743635376$$