El gráfico de la función cruce el eje X con f = 0
o sea hay que resolver la ecuación:
$$\sin{\left(4 x \right)} + \cos{\left(4 x \right)} = 0$$
Resolvermos esta ecuaciónPuntos de cruce con el eje X:
Solución analítica$$x_{1} = - \frac{\pi}{16}$$
Solución numérica$$x_{1} = -81.877758534184$$
$$x_{2} = 100.334615374024$$
$$x_{3} = -30.0414797499524$$
$$x_{4} = 60.2793090407542$$
$$x_{5} = -41.8224522009141$$
$$x_{6} = -67.7405915930299$$
$$x_{7} = -27.6852852597601$$
$$x_{8} = 57.9231145505618$$
$$x_{9} = -93.6587309851457$$
$$x_{10} = 75.9872723087031$$
$$x_{11} = -22.1874981159779$$
$$x_{12} = -37.8954613839269$$
$$x_{13} = -52.0326283250809$$
$$x_{14} = -1.76714586764426$$
$$x_{15} = -66.169795266235$$
$$x_{16} = 10.0138265833175$$
$$x_{17} = 6.08683576633022$$
$$x_{18} = 86.1974484328699$$
$$x_{19} = -49.6764338348886$$
$$x_{20} = 79.9142631256904$$
$$x_{21} = 21.7947990342792$$
$$x_{22} = -4.1233403578366$$
$$x_{23} = -59.8866099590554$$
$$x_{24} = 17.8678082172919$$
$$x_{25} = -9.62112750161874$$
$$x_{26} = -13.548118318606$$
$$x_{27} = 61.8501053675491$$
$$x_{28} = -77.9507677171967$$
$$x_{29} = 32.004975158446$$
$$x_{30} = -15.9043128087983$$
$$x_{31} = -70.0967860832223$$
$$x_{32} = 97.9784208838317$$
$$x_{33} = 94.0514300668444$$
$$x_{34} = -11.9773219918111$$
$$x_{35} = -99.9419162923253$$
$$x_{36} = 44.5713457728052$$
$$x_{37} = -44.1786466911065$$
$$x_{38} = 304.538137857361$$
$$x_{39} = 74.4164759819082$$
$$x_{40} = 78.3434667988955$$
$$x_{41} = 34.3611696486384$$
$$x_{42} = -45.7494430179014$$
$$x_{43} = 42.2151512826128$$
$$x_{44} = 64.2062998577414$$
$$x_{45} = -97.585721802133$$
$$x_{46} = -23.7582944427728$$
$$x_{47} = 38.2881604656256$$
$$x_{48} = 83.8412539426776$$
$$x_{49} = 50.0691329165873$$
$$x_{50} = 96.4076245570368$$
$$x_{51} = -43.393248527709$$
$$x_{52} = -33.9684705669396$$
$$x_{53} = -0.196349540849362$$
$$x_{54} = -96.0149254753381$$
$$x_{55} = -88.1609438413636$$
$$x_{56} = -89.7317401681585$$
$$x_{57} = -31.6122760767473$$
$$x_{58} = 82.2704576158827$$
$$x_{59} = -5.6941366846315$$
$$x_{60} = -71.6675824100172$$
$$x_{61} = 90.1244392498572$$
$$x_{62} = -19.8313036257856$$
$$x_{63} = -62.2428044492478$$
$$x_{64} = -34.7538687303371$$
$$x_{65} = 39.8589567924205$$
$$x_{66} = -56.7450173054656$$
$$x_{67} = 20.2240027074843$$
$$x_{68} = -55.9596191420682$$
$$x_{69} = 43.0005494460103$$
$$x_{70} = -8.05033117482385$$
$$x_{71} = 72.0602814917159$$
$$x_{72} = -63.8136007760427$$
$$x_{73} = 52.4253274067797$$
$$x_{74} = 24.1509935244715$$
$$x_{75} = 12.3700210735098$$
$$x_{76} = -53.6034246518758$$
$$x_{77} = -92.0879346583508$$
$$x_{78} = 35.9319659754333$$
$$x_{79} = -75.5945732270044$$
$$x_{80} = 2.15984494934298$$
$$x_{81} = 53.9961237335746$$
$$x_{82} = 16.2970118904971$$
$$x_{83} = 28.0779843414588$$
$$x_{84} = -48.1056375080937$$
$$x_{85} = 8.44303025652257$$
$$x_{86} = -74.0237769002095$$
$$x_{87} = 13.9408174003047$$
$$x_{88} = -85.8047493511712$$
$$x_{89} = 46.1421420996001$$
$$x_{90} = 68.1332906747286$$
$$x_{91} = 30.4341788316511$$
$$x_{92} = 41.4297531192154$$
$$x_{93} = 56.3523182237669$$
$$x_{94} = -26.1144889329652$$