El gráfico de la función cruce el eje X con f = 0
o sea hay que resolver la ecuación:
$$\sin{\left(x \right)} \sin{\left(3 x \right)} = 0$$
Resolvermos esta ecuaciónPuntos de cruce con el eje X:
Solución analítica$$x_{1} = 0$$
Solución numérica$$x_{1} = -21.9911485865076$$
$$x_{2} = -43.9822971748057$$
$$x_{3} = -94.2477795007104$$
$$x_{4} = -24.0855436775217$$
$$x_{5} = -15.707963296108$$
$$x_{6} = -46.0766922526503$$
$$x_{7} = 75.3982236924273$$
$$x_{8} = -4.18879020478639$$
$$x_{9} = -57.5958653158129$$
$$x_{10} = 90.0589894029074$$
$$x_{11} = 76.4454212373516$$
$$x_{12} = -72.2566309262098$$
$$x_{13} = -50.2654823521144$$
$$x_{14} = -79.5870138909414$$
$$x_{15} = -28.2743337784666$$
$$x_{16} = 8.37758040957278$$
$$x_{17} = 4.18879020478639$$
$$x_{18} = 34.5575190978177$$
$$x_{19} = 98.4365698124802$$
$$x_{20} = -75.3982237427215$$
$$x_{21} = 12.5663705268849$$
$$x_{22} = -97.3893723046965$$
$$x_{23} = -97.3893723140246$$
$$x_{24} = -6.28318520531977$$
$$x_{25} = 46.0766922526503$$
$$x_{26} = -53.4070751780852$$
$$x_{27} = 56.5486676696959$$
$$x_{28} = 6.28318528449741$$
$$x_{29} = -41.8879020478639$$
$$x_{30} = -92.1533845053006$$
$$x_{31} = 6.2831852928604$$
$$x_{32} = -31.4159264982662$$
$$x_{33} = 21.9911485851418$$
$$x_{34} = 39.7935069454707$$
$$x_{35} = -39.7935069454707$$
$$x_{36} = 0$$
$$x_{37} = 33.5103216382911$$
$$x_{38} = -13.6135681655558$$
$$x_{39} = -75.3982232420527$$
$$x_{40} = 72.2566310277269$$
$$x_{41} = 19.8967534727354$$
$$x_{42} = 65.9734457524179$$
$$x_{43} = -48.1710873550435$$
$$x_{44} = -75.3982234563503$$
$$x_{45} = 41.8879020478639$$
$$x_{46} = 63.8790506229925$$
$$x_{47} = 68.0678408277789$$
$$x_{48} = 74.3510261349584$$
$$x_{49} = -90.0589894029074$$
$$x_{50} = 84.823001664144$$
$$x_{51} = 50.2654824463941$$
$$x_{52} = -85.870199198121$$
$$x_{53} = 78.539816242374$$
$$x_{54} = -61.7846555205993$$
$$x_{55} = 81.6814090805726$$
$$x_{56} = 87.9645943349125$$
$$x_{57} = -12.5663703728218$$
$$x_{58} = -2.0943951023932$$
$$x_{59} = -87.9645943596624$$
$$x_{60} = -31.4159266113445$$
$$x_{61} = -35.6047167406843$$
$$x_{62} = 26.1799387799149$$
$$x_{63} = 52.3598775598299$$
$$x_{64} = 54.4542726622231$$
$$x_{65} = -9.42477804291614$$
$$x_{66} = 43.9822971692115$$
$$x_{67} = 96.342174710087$$
$$x_{68} = 59.6902605103337$$
$$x_{69} = -19.8967534727354$$
$$x_{70} = 37.6991119391801$$
$$x_{71} = -81.6814090367173$$
$$x_{72} = 100.530964815737$$
$$x_{73} = -68.0678408277789$$
$$x_{74} = 85.870199198121$$
$$x_{75} = -70.162235930172$$
$$x_{76} = -52.3598775598299$$
$$x_{77} = 28.2743338653253$$
$$x_{78} = -83.7758040957278$$
$$x_{79} = 60.7374579694027$$
$$x_{80} = 15.7079633672581$$
$$x_{81} = 70.162235930172$$
$$x_{82} = -37.6991118765052$$
$$x_{83} = -17.8023583703422$$
$$x_{84} = 2.0943951023932$$
$$x_{85} = 94.2477796093533$$
$$x_{86} = 48.1710873550435$$
$$x_{87} = 24.0855436775217$$
$$x_{88} = -21.9911487680291$$
$$x_{89} = -65.973445765529$$
$$x_{90} = -63.8790506229925$$
$$x_{91} = 92.1533845053006$$
$$x_{92} = -59.6902604567055$$
$$x_{93} = 720.471915223259$$
$$x_{94} = 17.8023583703422$$
$$x_{95} = -26.1799387799149$$
$$x_{96} = 30.3687289847013$$