El gráfico de la función cruce el eje X con f = 0
o sea hay que resolver la ecuación:
$$\frac{\left(-1\right) 6 \sin{\left(5 x \right)}}{169} - \frac{5 \cos{\left(5 x \right)}}{338} = 0$$
Resolvermos esta ecuaciónPuntos de cruce con el eje X:
Solución analítica$$x_{1} = - \frac{\operatorname{atan}{\left(\frac{5}{12} \right)}}{5}$$
Solución numérica$$x_{1} = 33.2219239041119$$
$$x_{2} = -7.61878059255546$$
$$x_{3} = 30.0803312505221$$
$$x_{4} = 80.3458137079588$$
$$x_{5} = 26.3104200662143$$
$$x_{6} = 91.0272287301641$$
$$x_{7} = 8.71750120611147$$
$$x_{8} = -44.0612553741971$$
$$x_{9} = -0.0789582239399523$$
$$x_{10} = 84.1157248922665$$
$$x_{11} = 28.1953756583682$$
$$x_{12} = -69.8223151336334$$
$$x_{13} = 36.3635165577017$$
$$x_{14} = -35.8931144748636$$
$$x_{15} = 20.0272347590347$$
$$x_{16} = -39.0347071284534$$
$$x_{17} = 96.0537769759077$$
$$x_{18} = -55.9993074578383$$
$$x_{19} = 82.2307693001126$$
$$x_{20} = 70.2927172164714$$
$$x_{21} = 40.1334277420094$$
$$x_{22} = 76.575902523651$$
$$x_{23} = 53.9564354178045$$
$$x_{24} = 43.9033389263172$$
$$x_{25} = -83.6453228094284$$
$$x_{26} = 92.2838657916$$
$$x_{27} = -29.609929167684$$
$$x_{28} = 47.6732501106249$$
$$x_{29} = -88.0435525244542$$
$$x_{30} = 87.8856360765743$$
$$x_{31} = -10.1320547154273$$
$$x_{32} = 38.2484721498555$$
$$x_{33} = 94.1688213837539$$
$$x_{34} = -94.3267378316337$$
$$x_{35} = -2454.29113920829$$
$$x_{36} = -3.8488694082477$$
$$x_{37} = -76.1055004408129$$
$$x_{38} = -45.9462109663509$$
$$x_{39} = -98.0966490159415$$
$$x_{40} = 75.947583992933$$
$$x_{41} = -39.6630256591713$$
$$x_{42} = 8.08918267539351$$
$$x_{43} = 4.31927149108576$$
$$x_{44} = -71.7072707257872$$
$$x_{45} = 91.655547260882$$
$$x_{46} = -27.7249735755301$$
$$x_{47} = -80.5037301558387$$
$$x_{48} = -57.8842630499921$$
$$x_{49} = -12.0170103075812$$
$$x_{50} = 11.8590938597013$$
$$x_{51} = 62.124576317138$$
$$x_{52} = -79.8754116251207$$
$$x_{53} = -5.73382500040158$$
$$x_{54} = -66.0524039493256$$
$$x_{55} = -34.0081588827097$$
$$x_{56} = 64.0095319092918$$
$$x_{57} = 65.8944875014457$$
$$x_{58} = -81.7603672172746$$
$$x_{59} = -22.0701067990685$$
$$x_{60} = 50.1865242334967$$
$$x_{61} = -1.96391381609383$$
$$x_{62} = 48.3015686413429$$
$$x_{63} = -50.9727592120946$$
$$x_{64} = -37.7780700670175$$
$$x_{65} = 52.0714798256506$$
$$x_{66} = -65.4240854186076$$
$$x_{67} = 58.3546651328302$$
$$x_{68} = -23.9550623912224$$
$$x_{69} = 86.0006804844204$$
$$x_{70} = -59.769218642146$$
$$x_{71} = -17.6718770840428$$
$$x_{72} = -99.9816046080954$$
$$x_{73} = -77.9904560329668$$
$$x_{74} = -15.7869214918889$$
$$x_{75} = 6.20422708323963$$
$$x_{76} = -47.8311665585048$$
$$x_{77} = 97.9387325680616$$
$$x_{78} = -32.1232032905558$$
$$x_{79} = 74.0626284007792$$
$$x_{80} = 9.97413826754739$$
$$x_{81} = -91.8134637087619$$
$$x_{82} = 42.0183833341633$$
$$x_{83} = -54.1143518656844$$
$$x_{84} = -93.6984193009158$$
$$x_{85} = -25.8400179833763$$
$$x_{86} = 21.9121903511886$$
$$x_{87} = -89.928508116608$$
$$x_{88} = 16.257323574727$$
$$x_{89} = 14.3723679825731$$
$$x_{90} = 31.9652868426759$$
$$x_{91} = -67.9373595414795$$
$$x_{92} = 60.2396207249841$$
$$x_{93} = 18.1422791668808$$
$$x_{94} = -13.901965899735$$
$$x_{95} = -61.6541742342999$$
$$x_{96} = 72.1776728086253$$
$$x_{97} = -49.7161221506587$$