El gráfico de la función cruce el eje X con f = 0
o sea hay que resolver la ecuación:
$$\cos^{3}{\left(4 x + 1 \right)} = 0$$
Resolvermos esta ecuaciónPuntos de cruce con el eje X:
Solución analítica$$x_{1} = - \frac{1}{4} + \frac{\pi}{8}$$
$$x_{2} = - \frac{1}{4} + \frac{3 \pi}{8}$$
Solución numérica$$x_{1} = -32.0586075224121$$
$$x_{2} = 70.0431223812214$$
$$x_{3} = -7.71129243054787$$
$$x_{4} = -68.186920732215$$
$$x_{5} = -69.7577354359186$$
$$x_{6} = 51.978985028971$$
$$x_{7} = -91.748886327692$$
$$x_{8} = -46.1957775695852$$
$$x_{9} = 73.9701364489236$$
$$x_{10} = 29.9878334877946$$
$$x_{11} = -95.6758946298345$$
$$x_{12} = 11.9236935653758$$
$$x_{13} = -87.0364933804102$$
$$x_{14} = -2.21350263266252$$
$$x_{15} = 48.0519721240686$$
$$x_{16} = 24.4900307471953$$
$$x_{17} = -73.6847442252381$$
$$x_{18} = 41.7687935739741$$
$$x_{19} = 58.2621599953572$$
$$x_{20} = 22.1338528683556$$
$$x_{21} = -81.5387065049916$$
$$x_{22} = 98.3174530944143$$
$$x_{23} = 4.06967341587778$$
$$x_{24} = 6.4258602204523$$
$$x_{25} = -76.0409094247717$$
$$x_{26} = 33.9148437833559$$
$$x_{27} = -13.9944697768351$$
$$x_{28} = 77.8971435338184$$
$$x_{29} = 76.3263027173725$$
$$x_{30} = 90.4634950831511$$
$$x_{31} = -61.9037693043557$$
$$x_{32} = -47.7665845671657$$
$$x_{33} = 50.4081549114766$$
$$x_{34} = -55.620596522677$$
$$x_{35} = 10.3528523482873$$
$$x_{36} = -33.6294471044309$$
$$x_{37} = 26.060822450009$$
$$x_{38} = -10.0674568722104$$
$$x_{39} = 18.2068675302449$$
$$x_{40} = -24.2046377333468$$
$$x_{41} = -11.6382974708957$$
$$x_{42} = 54.3351524585834$$
$$x_{43} = -17.9214691757026$$
$$x_{44} = 7.99668186727015$$
$$x_{45} = 28.4170071582033$$
$$x_{46} = 94.3904519993199$$
$$x_{47} = 46.4812073564023$$
$$x_{48} = 44.1249962296725$$
$$x_{49} = 40.1980178750655$$
$$x_{50} = -29.7024431147177$$
$$x_{51} = 36.2710091378088$$
$$x_{52} = 80.2533108806463$$
$$x_{53} = -35.9856213725121$$
$$x_{54} = -43.8395834766647$$
$$x_{55} = -99.6028945328542$$
$$x_{56} = 14.2798583244635$$
$$x_{57} = -65.0453405666184$$
$$x_{58} = 32.3440023306833$$
$$x_{59} = 66.116139591136$$
$$x_{60} = 92.0342731333503$$
$$x_{61} = -37.5564293388939$$
$$x_{62} = 62.1891679021945$$
$$x_{63} = 0.142708699184888$$
$$x_{64} = -83.8949149510114$$
$$x_{65} = -54.0497583768808$$
$$x_{66} = -15.5652855040093$$
$$x_{67} = 55.9059937751624$$
$$x_{68} = -90.1780659270506$$
$$x_{69} = 72.3993032413293$$
$$x_{70} = -87.8218801394642$$
$$x_{71} = 95.9612877169199$$
$$x_{72} = -57.9767728304856$$
$$x_{73} = -79.9679240459131$$
$$x_{74} = -54.835183512094$$
$$x_{75} = -25.7754337535868$$
$$x_{76} = -59.547570163291$$
$$x_{77} = 59.832985817167$$
$$x_{78} = -21.8484367308533$$
$$x_{79} = 88.1072837496463$$
$$x_{80} = 68.4723619222192$$
$$x_{81} = 81.8241324822372$$
$$x_{82} = -3.78428303647147$$
$$x_{83} = -65.8307313611828$$
$$x_{84} = -94.1050539934047$$
$$x_{85} = 84.1803174828971$$
$$x_{86} = -17.9214749417494$$
$$x_{87} = -39.9126225625605$$
$$x_{88} = -98.0320606513163$$
$$x_{89} = -51.6935937165855$$
$$x_{90} = 19.7776306673603$$
$$x_{91} = -77.6117456848833$$