El gráfico de la función cruce el eje X con f = 0
o sea hay que resolver la ecuación:
$$\sin{\left(2 x \right)} + \cos{\left(4 x \right)} = 0$$
Resolvermos esta ecuaciónPuntos de cruce con el eje X:
Solución analítica$$x_{1} = - \frac{3 \pi}{4}$$
$$x_{2} = - \frac{5 \pi}{12}$$
$$x_{3} = - \frac{\pi}{12}$$
$$x_{4} = \frac{\pi}{4}$$
$$x_{5} = \frac{7 \pi}{12}$$
$$x_{6} = \frac{11 \pi}{12}$$
Solución numérica$$x_{1} = 78.2780169519457$$
$$x_{2} = 19.6349541323512$$
$$x_{3} = 23.8237442897226$$
$$x_{4} = -69.3768377667746$$
$$x_{5} = 74.0892267471593$$
$$x_{6} = -68.3296401360248$$
$$x_{7} = 60.4756584824658$$
$$x_{8} = 82.4668070589037$$
$$x_{9} = 6.02138591938044$$
$$x_{10} = -29.5833308213039$$
$$x_{11} = -73.565627971561$$
$$x_{12} = -27.4889358199597$$
$$x_{13} = -2.35619443976488$$
$$x_{14} = -37.9609112308767$$
$$x_{15} = 25.9181394569779$$
$$x_{16} = -5.49778724491704$$
$$x_{17} = 96.0803753222878$$
$$x_{18} = 93.9859802198946$$
$$x_{19} = -81.9432083811338$$
$$x_{20} = 67.8060414399797$$
$$x_{21} = -11.7809724256434$$
$$x_{22} = -42.1497014356631$$
$$x_{23} = -9.68657734856853$$
$$x_{24} = -49.4800843945554$$
$$x_{25} = -62.0464548656356$$
$$x_{26} = -77.7544181730249$$
$$x_{27} = -7.59218224617533$$
$$x_{28} = 69.9004366161932$$
$$x_{29} = -79.8488132787406$$
$$x_{30} = 38.4845099063309$$
$$x_{31} = -24.3473433992227$$
$$x_{32} = 52.0980781720307$$
$$x_{33} = -75.6600230739542$$
$$x_{34} = -15.9697626557481$$
$$x_{35} = -93.4623815421655$$
$$x_{36} = 45.8148928648512$$
$$x_{37} = 57.3340658345832$$
$$x_{38} = -40.0553062843717$$
$$x_{39} = -24.3473430030571$$
$$x_{40} = -97.6511716490827$$
$$x_{41} = 98.174770499714$$
$$x_{42} = 100.269165527074$$
$$x_{43} = -95.5567765466895$$
$$x_{44} = 50.0036830696375$$
$$x_{45} = 1.83259571459405$$
$$x_{46} = -13.8753675533549$$
$$x_{47} = -31.6777259236971$$
$$x_{48} = -59.9520598060052$$
$$x_{49} = -55.7632695909785$$
$$x_{50} = 19.6349541205733$$
$$x_{51} = 8.11578102177363$$
$$x_{52} = -46.3384915686405$$
$$x_{53} = 16.493361330526$$
$$x_{54} = -90.3207887048455$$
$$x_{55} = -86.1319985859202$$
$$x_{56} = 28.012534494509$$
$$x_{57} = -84.0376034473962$$
$$x_{58} = -66.2352451131848$$
$$x_{59} = -33.7721210085396$$
$$x_{60} = 41.6261026770585$$
$$x_{61} = 76.1836219126294$$
$$x_{62} = -18.0641577035443$$
$$x_{63} = 63.6172512284748$$
$$x_{64} = -71.4712329686473$$
$$x_{65} = 34.2957198016886$$
$$x_{66} = 3.9269908768935$$
$$x_{67} = 80.3724120543389$$
$$x_{68} = -57.857664703612$$
$$x_{69} = 56.2868683768171$$
$$x_{70} = -51.5744793964324$$
$$x_{71} = -20.1585528605345$$
$$x_{72} = 71.9948316447661$$
$$x_{73} = 58.3812634792103$$
$$x_{74} = 41.6261024515687$$
$$x_{75} = 30.1069295969022$$
$$x_{76} = 89.7971900151083$$
$$x_{77} = 10.2101761577944$$
$$x_{78} = -44.2440965380563$$
$$x_{79} = 91.8915851953631$$
$$x_{80} = -2.35619464902022$$
$$x_{81} = 85.608400061628$$
$$x_{82} = 12.30457122656$$
$$x_{83} = 32.201324741883$$
$$x_{84} = -35.8665161284835$$
$$x_{85} = -64.1408500107916$$
$$x_{86} = 63.6172509684575$$
$$x_{87} = 36.3901149040818$$
$$x_{88} = 14.3989663289532$$
$$x_{89} = -82.9904059323304$$
$$x_{90} = -99.7455667547296$$
$$x_{91} = -109.170344829496$$
$$x_{92} = -53.6688744988256$$
$$x_{93} = 85.608399773204$$
$$x_{94} = 54.1924733267656$$
$$x_{95} = 47.9092880367371$$