El gráfico de la función cruce el eje X con f = 0
o sea hay que resolver la ecuación:
$$\cos{\left(3 x - 1 \right)} = 0$$
Resolvermos esta ecuaciónPuntos de cruce con el eje X:
Solución analítica$$x_{1} = \frac{1}{3} + \frac{\pi}{6}$$
$$x_{2} = \frac{1}{3} + \frac{\pi}{2}$$
Solución numérica$$x_{1} = 1.90412966012823$$
$$x_{2} = -61.9749209628642$$
$$x_{3} = -75.58848912842$$
$$x_{4} = -79.7772793332064$$
$$x_{5} = 25.98967333765$$
$$x_{6} = 80.4439459998731$$
$$x_{7} = -140.514737302609$$
$$x_{8} = 10.281710069701$$
$$x_{9} = 8.18731496730782$$
$$x_{10} = -97.5796377035486$$
$$x_{11} = -42.0781674901289$$
$$x_{12} = 87.7743288582492$$
$$x_{13} = -22.1814140173935$$
$$x_{14} = 52.1696121175649$$
$$x_{15} = -66.1637111676506$$
$$x_{16} = -51.5029454508983$$
$$x_{17} = 72.0663655903003$$
$$x_{18} = 12.3761051720942$$
$$x_{19} = -81.8716744355996$$
$$x_{20} = 45.8864268103853$$
$$x_{21} = 82.5383411022663$$
$$x_{22} = -2.28466054465816$$
$$x_{23} = -33.7005870805561$$
$$x_{24} = -11.7094385054275$$
$$x_{25} = -73.4940940260268$$
$$x_{26} = -46.2669576949153$$
$$x_{27} = 54.2640072199581$$
$$x_{28} = 56.3584023223513$$
$$x_{29} = -17.9926238126071$$
$$x_{30} = 78.3495508974799$$
$$x_{31} = 65.7831802831207$$
$$x_{32} = 32.2728586448296$$
$$x_{33} = -63.0221185140608$$
$$x_{34} = -49.4085503485051$$
$$x_{35} = -20.0870189150003$$
$$x_{36} = -55.6917356556846$$
$$x_{37} = 47.9808219127785$$
$$x_{38} = 94.0575141654288$$
$$x_{39} = -34.7477846317527$$
$$x_{40} = -88.1548597427792$$
$$x_{41} = -31.6061919781629$$
$$x_{42} = -90.2492548451724$$
$$x_{43} = -44.1725625925221$$
$$x_{44} = -39.9837723877357$$
$$x_{45} = 91.9631190630356$$
$$x_{46} = -29.5117968757697$$
$$x_{47} = -37.8893772853425$$
$$x_{48} = 3.99852476252143$$
$$x_{49} = -0.190265442264966$$
$$x_{50} = 69.9719704879071$$
$$x_{51} = -99.6740328059417$$
$$x_{52} = -7.52064830064115$$
$$x_{53} = -24.2758091197867$$
$$x_{54} = -77.6828842308132$$
$$x_{55} = 28.0840684400432$$
$$x_{56} = 67.8775753855139$$
$$x_{57} = -35.7949821829493$$
$$x_{58} = -53.5973405532915$$
$$x_{59} = 36.461648849616$$
$$x_{60} = 96.151909267822$$
$$x_{61} = -13.8038336078207$$
$$x_{62} = 58.4527974247445$$
$$x_{63} = -9.61504340303435$$
$$x_{64} = -59.880525860471$$
$$x_{65} = -95.4852426011554$$
$$x_{66} = 83.5855386534628$$
$$x_{67} = 43.7920317079921$$
$$x_{68} = 14.4705002744874$$
$$x_{69} = -30.5589944269663$$
$$x_{70} = 98.2463043702152$$
$$x_{71} = -91.296452396369$$
$$x_{72} = 21.8008831328636$$
$$x_{73} = -68.2581062700438$$
$$x_{74} = -26.3702042221799$$
$$x_{75} = -83.9660695379928$$
$$x_{76} = -15.8982287102139$$
$$x_{77} = 19.7064880304704$$
$$x_{78} = 89.8687239606424$$
$$x_{79} = 23.8952782352568$$
$$x_{80} = 6.09291986491462$$
$$x_{81} = -86.060464640386$$
$$x_{82} = 30.1784635424364$$
$$x_{83} = 76.2551557950867$$
$$x_{84} = 34.3672537472228$$
$$x_{85} = 74.1607606926935$$
$$x_{86} = -4.37905564705136$$
$$x_{87} = -57.7861307580778$$
$$x_{88} = -64.0693160652574$$
$$x_{89} = 41.6976366055989$$
$$x_{90} = 84.6327362046595$$
$$x_{91} = 60.5471925271377$$
$$x_{92} = 100.340699472608$$
$$x_{93} = 38.5560439520091$$
$$x_{94} = 9.23451251850442$$
$$x_{95} = 50.0752170151717$$