El gráfico de la función cruce el eje X con f = 0
o sea hay que resolver la ecuación:
$$\sin{\left(2 x \right)} \cos{\left(3 x \right)} + \sin{\left(3 x \right)} \cos{\left(2 x \right)} = 0$$
Resolvermos esta ecuaciónPuntos de cruce con el eje X:
Solución analítica$$x_{1} = 0$$
$$x_{2} = - \frac{9 \pi}{5}$$
$$x_{3} = - \frac{8 \pi}{5}$$
$$x_{4} = - \frac{6 \pi}{5}$$
$$x_{5} = - \pi$$
$$x_{6} = - \frac{4 \pi}{5}$$
$$x_{7} = - \frac{2 \pi}{5}$$
$$x_{8} = \frac{\pi}{5}$$
$$x_{9} = \frac{2 \pi}{5}$$
$$x_{10} = \frac{4 \pi}{5}$$
$$x_{11} = \pi$$
$$x_{12} = \frac{6 \pi}{5}$$
$$x_{13} = \frac{8 \pi}{5}$$
$$x_{14} = 2 \pi$$
$$x_{15} = - 2 i \log{\left(- \frac{\sqrt{10} \sqrt{\sqrt{5} + 5}}{8} + \frac{\sqrt{2} \sqrt{\sqrt{5} + 5}}{8} + \frac{i}{4} + \frac{\sqrt{5} i}{4} \right)}$$
$$x_{16} = - 2 i \log{\left(- \frac{\sqrt{2} \sqrt{\sqrt{5} + 5}}{8} + \frac{\sqrt{10} \sqrt{\sqrt{5} + 5}}{8} - \frac{\sqrt{5} i}{4} - \frac{i}{4} \right)}$$
$$x_{17} = - 2 i \log{\left(- \frac{\sqrt{10} \sqrt{5 - \sqrt{5}}}{16} + \frac{\sqrt{2} \sqrt{5 - \sqrt{5}}}{16} + \frac{\sqrt{2} \sqrt{\sqrt{5} + 5}}{16} + \frac{\sqrt{10} \sqrt{\sqrt{5} + 5}}{16} + \frac{i}{4} + \frac{\sqrt{5} i}{4} \right)}$$
$$x_{18} = - 2 i \log{\left(- \frac{\sqrt{10} \sqrt{\sqrt{5} + 5}}{16} - \frac{\sqrt{10} \sqrt{5 - \sqrt{5}}}{16} - \frac{\sqrt{2} \sqrt{\sqrt{5} + 5}}{16} + \frac{\sqrt{2} \sqrt{5 - \sqrt{5}}}{16} - \frac{i}{4} + \frac{\sqrt{5} i}{4} \right)}$$
$$x_{19} = - 2 i \log{\left(- \frac{\sqrt{10} \sqrt{\sqrt{5} + 5}}{16} - \frac{\sqrt{2} \sqrt{\sqrt{5} + 5}}{16} - \frac{\sqrt{2} \sqrt{5 - \sqrt{5}}}{16} + \frac{\sqrt{10} \sqrt{5 - \sqrt{5}}}{16} - \frac{\sqrt{5} i}{4} - \frac{i}{4} \right)}$$
$$x_{20} = - 2 i \log{\left(- \frac{\sqrt{2} \sqrt{5 - \sqrt{5}}}{16} + \frac{\sqrt{2} \sqrt{\sqrt{5} + 5}}{16} + \frac{\sqrt{10} \sqrt{5 - \sqrt{5}}}{16} + \frac{\sqrt{10} \sqrt{\sqrt{5} + 5}}{16} - \frac{\sqrt{5} i}{4} + \frac{i}{4} \right)}$$
Solución numérica$$x_{1} = -42.0973415581032$$
$$x_{2} = 45.867252742411$$
$$x_{3} = -15.707963267949$$
$$x_{4} = -57.8053048260522$$
$$x_{5} = 55.9203492338983$$
$$x_{6} = 8.16814089933346$$
$$x_{7} = 26.3893782901543$$
$$x_{8} = 21.9911485751286$$
$$x_{9} = 0$$
$$x_{10} = -21.9911485751286$$
$$x_{11} = -64.0884901332318$$
$$x_{12} = 28.2743338823081$$
$$x_{13} = 48.3805268652828$$
$$x_{14} = -93.6194610769758$$
$$x_{15} = 72.2566310325652$$
$$x_{16} = -35.8141562509236$$
$$x_{17} = -47.7522083345649$$
$$x_{18} = -3.76991118430775$$
$$x_{19} = -76.026542216873$$
$$x_{20} = 87.9645943005142$$
$$x_{21} = -43.9822971502571$$
$$x_{22} = 50.2654824574367$$
$$x_{23} = -74.1415866247191$$
$$x_{24} = 16.3362817986669$$
$$x_{25} = 189.752196276824$$
$$x_{26} = -89.8495498926681$$
$$x_{27} = 52.1504380495906$$
$$x_{28} = 18.2212373908208$$
$$x_{29} = -98.0176907920015$$
$$x_{30} = -81.6814089933346$$
$$x_{31} = -77.9114978090269$$
$$x_{32} = 94.2477796076938$$
$$x_{33} = 38.3274303737955$$
$$x_{34} = -91.734505484822$$
$$x_{35} = -20.1061929829747$$
$$x_{36} = -32.0442450666159$$
$$x_{37} = 67.8584013175395$$
$$x_{38} = 30.159289474462$$
$$x_{39} = -13.8230076757951$$
$$x_{40} = -10.0530964914873$$
$$x_{41} = 42.0973415581032$$
$$x_{42} = -33.9292006587698$$
$$x_{43} = -79.7964534011807$$
$$x_{44} = -23.8761041672824$$
$$x_{45} = 65.9734457253857$$
$$x_{46} = 101.159283445591$$
$$x_{47} = 98.0176907920015$$
$$x_{48} = 70.3716754404114$$
$$x_{49} = 20.1061929829747$$
$$x_{50} = -54.0353936417444$$
$$x_{51} = 62.2035345410779$$
$$x_{52} = 32.0442450666159$$
$$x_{53} = 54.0353936417444$$
$$x_{54} = -87.9645943005142$$
$$x_{55} = 77.9114978090269$$
$$x_{56} = 5.02654824574367$$
$$x_{57} = -27.6460153515902$$
$$x_{58} = 99.9026463841554$$
$$x_{59} = 60.318578948924$$
$$x_{60} = 11.3097335529233$$
$$x_{61} = 64.0884901332318$$
$$x_{62} = 11.9380520836412$$
$$x_{63} = -11.9380520836412$$
$$x_{64} = -65.9734457253857$$
$$x_{65} = 92.3628240155399$$
$$x_{66} = 43.9822971502571$$
$$x_{67} = 84.1946831162065$$
$$x_{68} = -49.6371639267187$$
$$x_{69} = -37.6991118430775$$
$$x_{70} = -59.6902604182061$$
$$x_{71} = 33.9292006587698$$
$$x_{72} = 86.0796387083603$$
$$x_{73} = 40.2123859659494$$
$$x_{74} = -96.1327351998477$$
$$x_{75} = 82.3097275240526$$
$$x_{76} = -5.65486677646163$$
$$x_{77} = 89.2212313619501$$
$$x_{78} = 76.026542216873$$
$$x_{79} = -71.6283125018473$$
$$x_{80} = -55.9203492338983$$
$$x_{81} = 6.28318530717959$$
$$x_{82} = -45.867252742411$$
$$x_{83} = -69.7433569096934$$
$$x_{84} = -1.88495559215388$$
$$x_{85} = 74.1415866247191$$
$$x_{86} = 10.0530964914873$$
$$x_{87} = 1.88495559215388$$
$$x_{88} = 23.8761041672824$$
$$x_{89} = -25.7610597594363$$
$$x_{90} = 5.65486677646163$$
$$x_{91} = -99.9026463841554$$
$$x_{92} = -86.0796387083603$$
$$x_{93} = -67.8584013175395$$
$$x_{94} = -52.7787565803085$$
$$x_{95} = 96.1327351998477$$