El gráfico de la función cruce el eje X con f = 0
o sea hay que resolver la ecuación:
$$3 \sin{\left(3 x \right)} + 2 \cos{\left(2 x \right)} = 0$$
Resolvermos esta ecuaciónPuntos de cruce con el eje X:
Solución numérica$$x_{1} = -39.6128030260435$$
$$x_{2} = 74.1703222155312$$
$$x_{3} = 48.3517912744707$$
$$x_{4} = 66.1900652499754$$
$$x_{5} = -21.7745290505388$$
$$x_{6} = -45.8959883332231$$
$$x_{7} = -61.8645090696466$$
$$x_{8} = 16.9358647385728$$
$$x_{9} = 56.3320482400265$$
$$x_{10} = -72.0400115079754$$
$$x_{11} = -88.181213825104$$
$$x_{12} = 93.01987813707$$
$$x_{13} = 22.2077680997183$$
$$x_{14} = 87.7479747759244$$
$$x_{15} = -68.1476943768262$$
$$x_{16} = -96.1614707906598$$
$$x_{17} = 7.25052930932882$$
$$x_{18} = 94.031160083104$$
$$x_{19} = 96.4220282591344$$
$$x_{20} = -41.8080484988165$$
$$x_{21} = -31.6325460604877$$
$$x_{22} = 39.8733604945181$$
$$x_{23} = 26.1000852308676$$
$$x_{24} = -11.5990266122099$$
$$x_{25} = -177.842879783994$$
$$x_{26} = 52.4397311088773$$
$$x_{27} = 5.05528383655578$$
$$x_{28} = -28.0577143577183$$
$$x_{29} = 92.3340884247278$$
$$x_{30} = -13.794272084983$$
$$x_{31} = 70.0823823811247$$
$$x_{32} = -15.4913437433592$$
$$x_{33} = -64.0597545424197$$
$$x_{34} = 4.3694941242136$$
$$x_{35} = -12.782990138949$$
$$x_{36} = -57.7765692352401$$
$$x_{37} = -79.5071603418941$$
$$x_{38} = -4.10893665573902$$
$$x_{39} = 60.9181618888299$$
$$x_{40} = 76.3655676883043$$
$$x_{41} = -81.8980285179244$$
$$x_{42} = 72.473250557155$$
$$x_{43} = -55.5813237624671$$
$$x_{44} = 6.06656578258979$$
$$x_{45} = 15.9245827925388$$
$$x_{46} = -35.524863191637$$
$$x_{47} = 67.8871369083516$$
$$x_{48} = -32.6438280065217$$
$$x_{49} = -33.3296177188639$$
$$x_{50} = 83.8556576447752$$
$$x_{51} = 43.7656776256673$$
$$x_{52} = 46.1565458016977$$
$$x_{53} = 23.9048397580945$$
$$x_{54} = 79.7677178103686$$
$$x_{55} = -17.8822119193895$$
$$x_{56} = 80.4535075227108$$
$$x_{57} = -71.0287295619414$$
$$x_{58} = 90.1388429519548$$
$$x_{59} = -20.0774573921626$$
$$x_{60} = -0.216619524589792$$
$$x_{61} = 19.816899923688$$
$$x_{62} = 8.45743395862015$$
$$x_{63} = 30.1880250652741$$
$$x_{64} = 100.314345390284$$
$$x_{65} = 28.4909534068979$$
$$x_{66} = 59.9068799427959$$
$$x_{67} = -99.5636209127241$$
$$x_{68} = 63.7991970739451$$
$$x_{69} = -51.4933839280605$$
$$x_{70} = -65.7568262007959$$
$$x_{71} = -8.19687649014558$$
$$x_{72} = -24.1653972265691$$
$$x_{73} = -92.0735309562532$$
$$x_{74} = -59.4736408936163$$
$$x_{75} = 32.3832705380472$$
$$x_{76} = -85.7903456490736$$
$$x_{77} = 61.6039516011721$$
$$x_{78} = -89.8782854834802$$
$$x_{79} = -20.7632471045047$$
$$x_{80} = 50.0488629328469$$
$$x_{81} = -76.6261251567788$$
$$x_{82} = 124.435804672968$$
$$x_{83} = -48.0912338059961$$
$$x_{84} = 42.0686059672911$$
$$x_{85} = -75.6148432107448$$
$$x_{86} = 2.17424865144056$$
$$x_{87} = -44.1989166748469$$
$$x_{88} = -37.9157313676673$$
$$x_{89} = 86.0509031175482$$
$$x_{90} = -83.5951001763006$$
$$x_{91} = 12.3497510897694$$
$$x_{92} = -1.91369118296599$$