El gráfico de la función cruce el eje X con f = 0
o sea hay que resolver la ecuación:
$$\sqrt{\sin{\left(3 x \right)} + 1} = 0$$
Resolvermos esta ecuaciónPuntos de cruce con el eje X:
Solución analítica$$x_{1} = - \frac{\pi}{6}$$
$$x_{2} = \frac{\pi}{2}$$
Solución numérica$$x_{1} = 9.94837673636768$$
$$x_{2} = 74.8746249105567$$
$$x_{3} = 24.60914245312$$
$$x_{4} = -86.3937979737193$$
$$x_{5} = 60.2138591938044$$
$$x_{6} = 1.5707963267949$$
$$x_{7} = 93.7241808320955$$
$$x_{8} = -25.6563400043166$$
$$x_{9} = -54.9778714378214$$
$$x_{10} = 89.5353906273091$$
$$x_{11} = -17.2787595947439$$
$$x_{12} = 45.553093477052$$
$$x_{13} = 64.4026493985908$$
$$x_{14} = -38.2227106186758$$
$$x_{15} = -57.0722665402146$$
$$x_{16} = -84.2994028713261$$
$$x_{17} = -29.845130209103$$
$$x_{18} = 20.4203522483337$$
$$x_{19} = 66.497044500984$$
$$x_{20} = 62.3082542961976$$
$$x_{21} = 22.5147473507269$$
$$x_{22} = 12.0427718387609$$
$$x_{23} = 70.6858347057703$$
$$x_{24} = -78.0162175641465$$
$$x_{25} = 100.007366139275$$
$$x_{26} = -515.744793964324$$
$$x_{27} = 5.75958653158129$$
$$x_{28} = -88.4881930761125$$
$$x_{29} = -42.4115008234622$$
$$x_{30} = -19.3731546971371$$
$$x_{31} = -67.5442420521806$$
$$x_{32} = -65.4498469497874$$
$$x_{33} = -23.5619449019235$$
$$x_{34} = 56.025068989018$$
$$x_{35} = -82.2050077689329$$
$$x_{36} = -34.0339204138894$$
$$x_{37} = -63.3554518473942$$
$$x_{38} = 91.6297857297023$$
$$x_{39} = -10.9955742875643$$
$$x_{40} = -36.1283155162826$$
$$x_{41} = 14.1371669411541$$
$$x_{42} = -40.317105721069$$
$$x_{43} = 97.9129710368819$$
$$x_{44} = 51.8362787842316$$
$$x_{45} = 53.9306738866248$$
$$x_{46} = 68.5914396033772$$
$$x_{47} = 3.66519142918809$$
$$x_{48} = 95.8185759344887$$
$$x_{49} = -71.733032256967$$
$$x_{50} = 16.2315620435473$$
$$x_{51} = -59.1666616426078$$
$$x_{52} = -80.1106126665397$$
$$x_{53} = 47.6474885794452$$
$$x_{54} = -73.8274273593601$$
$$x_{55} = -27.7507351067098$$
$$x_{56} = 7.85398163397448$$
$$x_{57} = 18.3259571459405$$
$$x_{58} = -21.4675497995303$$
$$x_{59} = 49.7418836818384$$
$$x_{60} = -69.6386371545737$$
$$x_{61} = 26.7035375555132$$