El gráfico de la función cruce el eje X con f = 0
o sea hay que resolver la ecuación:
$$\left(- \sin{\left(\frac{\sqrt{2} \cdot 4 x}{3} \right)} - \cos{\left(\frac{\sqrt{2} \cdot 4 x}{3} \right)}\right) e^{\frac{x}{3}} = 0$$
Resolvermos esta ecuaciónPuntos de cruce con el eje X:
Solución analítica$$x_{1} = - \frac{3 \sqrt{2} \pi}{32}$$
$$x_{2} = \frac{45 \sqrt{2} \pi}{32}$$
$$x_{3} = - \frac{3 \sqrt{2} i \log{\left(- \left(-1\right)^{\frac{3}{16}} \right)}}{2}$$
Solución numérica$$x_{1} = -45.4007100243058$$
$$x_{2} = 47.8998316770199$$
$$x_{3} = 74.5571293059701$$
$$x_{4} = -13.7451690899274$$
$$x_{5} = 67.8928048987325$$
$$x_{6} = -22.0755745989744$$
$$x_{7} = 17.9103718444509$$
$$x_{8} = 19.5764529462603$$
$$x_{9} = -53.7311155333527$$
$$x_{10} = 29.5729395571166$$
$$x_{11} = 89.5518592222546$$
$$x_{12} = 44.5676694734011$$
$$x_{13} = 36.2372639643542$$
$$x_{14} = 34.5711828625448$$
$$x_{15} = -102.047467485825$$
$$x_{16} = 57.8963182878762$$
$$x_{17} = -3.74868247907112$$
$$x_{18} = 42.9015883715917$$
$$x_{19} = -92.0509808749686$$
$$x_{20} = -60.3954399405903$$
$$x_{21} = -42.068547820687$$
$$x_{22} = -80.3884131623029$$
$$x_{23} = 56.2302371860668$$
$$x_{24} = 79.5553726113982$$
$$x_{25} = -10.4130068863087$$
$$x_{26} = -40.4024667188776$$
$$x_{27} = 6.2478041317852$$
$$x_{28} = -55.3971966351621$$
$$x_{29} = -63.7276021442091$$
$$x_{30} = 54.5641560842574$$
$$x_{31} = -85.3866564677311$$
$$x_{32} = -5.41476358088051$$
$$x_{33} = -70.3919265514466$$
$$x_{34} = 51.2319938806387$$
$$x_{35} = -90.3848997731593$$
$$x_{36} = 16.2442907426415$$
$$x_{37} = 26.2407773534979$$
$$x_{38} = 69.5588860005419$$
$$x_{39} = 66.2267237969232$$
$$x_{40} = -62.0615210423997$$
$$x_{41} = 61.228480491495$$
$$x_{42} = -82.0544942641123$$
$$x_{43} = -15.4112501917368$$
$$x_{44} = -20.409493497165$$
$$x_{45} = -95.3831430785874$$
$$x_{46} = -73.7240887550654$$
$$x_{47} = 7.91388523359459$$
$$x_{48} = 84.5536159168264$$
$$x_{49} = 87.8857781204452$$
$$x_{50} = 99.5483458331109$$
$$x_{51} = 46.2337505752105$$
$$x_{52} = 49.5659127788293$$
$$x_{53} = 59.5623993896856$$
$$x_{54} = 9.57996633540398$$
$$x_{55} = -43.7346289224964$$
$$x_{56} = -50.398953329734$$
$$x_{57} = -30.4059801080213$$
$$x_{58} = -35.4042234134495$$
$$x_{59} = 14.5782096408321$$
$$x_{60} = 39.5694261679729$$
$$x_{61} = -52.0650344315434$$
$$x_{62} = -0.416520275452347$$
$$x_{63} = 64.5606426951138$$
$$x_{64} = 86.2196970186358$$
$$x_{65} = -33.7381423116401$$
$$x_{66} = -65.3936832460185$$
$$x_{67} = 37.9033450661636$$
$$x_{68} = -83.7205753659217$$
$$x_{69} = -23.7416557007838$$
$$x_{70} = -32.0720612098307$$
$$x_{71} = -2.08260137726173$$
$$x_{72} = -72.058007653256$$
$$x_{73} = 4.58172302997581$$
$$x_{74} = -75.3901698568748$$
$$x_{75} = 77.8892915095889$$
$$x_{76} = -25.4077368025932$$
$$x_{77} = 76.2232104077795$$
$$x_{78} = 27.9068584553072$$
$$x_{79} = 24.5746962516885$$
$$x_{80} = -100.381386384016$$
$$x_{81} = -12.0790879881181$$
$$x_{82} = -93.717061976778$$