El gráfico de la función cruce el eje X con f = 0
o sea hay que resolver la ecuación:
$$\sin^{4}{\left(x \right)} \cos^{4}{\left(x \right)} = 0$$
Resolvermos esta ecuaciónPuntos de cruce con el eje X:
Solución analítica$$x_{1} = 0$$
$$x_{2} = - \frac{\pi}{2}$$
$$x_{3} = \frac{\pi}{2}$$
Solución numérica$$x_{1} = 36.1287270404635$$
$$x_{2} = -17.2795693336354$$
$$x_{3} = 20.4198938578894$$
$$x_{4} = 40.8412803201481$$
$$x_{5} = -87.9649089297233$$
$$x_{6} = 26.7027122852751$$
$$x_{7} = -45.55361243338$$
$$x_{8} = 92.6761520146476$$
$$x_{9} = -58.1190704762023$$
$$x_{10} = -37.699257578466$$
$$x_{11} = -39.2707053168922$$
$$x_{12} = -78.539288769567$$
$$x_{13} = -14.1367234757905$$
$$x_{14} = 34.556793894431$$
$$x_{15} = 84.823008882661$$
$$x_{16} = 45.5539375681816$$
$$x_{17} = 48.6938569047358$$
$$x_{18} = 4.711570058293$$
$$x_{19} = 73.8279624955149$$
$$x_{20} = 53.4063988271113$$
$$x_{21} = -61.2618371404185$$
$$x_{22} = 12.5656325168598$$
$$x_{23} = 0$$
$$x_{24} = -23.5624440926244$$
$$x_{25} = 9.42471436824845$$
$$x_{26} = -83.2529638110211$$
$$x_{27} = -9.42552822198168$$
$$x_{28} = -42.4106454421453$$
$$x_{29} = -56.5482370322897$$
$$x_{30} = 58.1200415970984$$
$$x_{31} = -1.57127532535339$$
$$x_{32} = -43.9823594344854$$
$$x_{33} = -31.4166882959688$$
$$x_{34} = 18.8505947368085$$
$$x_{35} = -36.1278966440531$$
$$x_{36} = -29.8448024535293$$
$$x_{37} = 29.8456208536012$$
$$x_{38} = 95.819132307389$$
$$x_{39} = 87.9647182234297$$
$$x_{40} = -34.5585553448323$$
$$x_{41} = -59.6904310844151$$
$$x_{42} = 89.536217941181$$
$$x_{43} = -12.5662278525543$$
$$x_{44} = 1.57164916844595$$
$$x_{45} = 67.5450789120991$$
$$x_{46} = 100.530281637373$$
$$x_{47} = -67.5447803370477$$
$$x_{48} = -65.9735393558215$$
$$x_{49} = 31.4156016124022$$
$$x_{50} = -50.264758101647$$
$$x_{51} = -72.2559214616046$$
$$x_{52} = 70.6850035717189$$
$$x_{53} = -7.85359457256807$$
$$x_{54} = 81.6822070096252$$
$$x_{55} = 28.2742638653839$$
$$x_{56} = -73.8271877015226$$
$$x_{57} = -100.530362747495$$
$$x_{58} = 23.5627942366716$$
$$x_{59} = 62.8321061467122$$
$$x_{60} = 43.982359346097$$
$$x_{61} = 21.9911796946073$$
$$x_{62} = -87.9647198348291$$
$$x_{63} = -1.57143266797598$$
$$x_{64} = 72.256611933245$$
$$x_{65} = -81.6816043860351$$
$$x_{66} = 64.4022334296609$$
$$x_{67} = -86.3929451509224$$
$$x_{68} = 65.9735388835578$$
$$x_{69} = -94.2470855153361$$
$$x_{70} = -67.5439773417704$$
$$x_{71} = -34.5572142139742$$
$$x_{72} = 94.2477860034114$$
$$x_{73} = 6.2830899289056$$
$$x_{74} = 59.6910480052874$$
$$x_{75} = -15.7080838968998$$
$$x_{76} = 56.5479558873923$$
$$x_{77} = 80.1114780933$$
$$x_{78} = 14.1376198244384$$
$$x_{79} = 86.393403796318$$
$$x_{80} = -20.4194974420078$$
$$x_{81} = 78.5391184747289$$
$$x_{82} = -64.4017947108781$$
$$x_{83} = 15.7087277408856$$
$$x_{84} = -28.2735954422807$$
$$x_{85} = -51.8359994869283$$
$$x_{86} = 42.4110634464906$$
$$x_{87} = 37.6998882441174$$
$$x_{88} = -97.3901642129298$$
$$x_{89} = 51.8367920108669$$
$$x_{90} = -6.28243349160182$$
$$x_{91} = -75.3990063274271$$
$$x_{92} = 7.85444902427444$$
$$x_{93} = -21.9911796999568$$
$$x_{94} = 50.2654378779391$$
$$x_{95} = -53.4078476756257$$
$$x_{96} = -89.5359477929329$$
$$x_{97} = -80.1102449654855$$
$$x_{98} = -95.8183699591765$$