El gráfico de la función cruce el eje P con f = 0
o sea hay que resolver la ecuación:
$$\cos{\left(2 p \right)} = 0$$
Resolvermos esta ecuaciónPuntos de cruce con el eje P:
Solución analítica$$p_{1} = \frac{\pi}{4}$$
$$p_{2} = \frac{3 \pi}{4}$$
Solución numérica$$p_{1} = 2.35619449019234$$
$$p_{2} = -11.7809724509617$$
$$p_{3} = -38.484510006475$$
$$p_{4} = 11.7809724509617$$
$$p_{5} = 46.3384916404494$$
$$p_{6} = 40.0553063332699$$
$$p_{7} = -68.329640215578$$
$$p_{8} = -32.2013246992954$$
$$p_{9} = -25.9181393921158$$
$$p_{10} = 33.7721210260903$$
$$p_{11} = 96.6039740978861$$
$$p_{12} = 55.7632696012188$$
$$p_{13} = 384.059701901352$$
$$p_{14} = 5.49778714378214$$
$$p_{15} = -18.0641577581413$$
$$p_{16} = -69.9004365423729$$
$$p_{17} = 18.0641577581413$$
$$p_{18} = -85.6083998103219$$
$$p_{19} = 47.9092879672443$$
$$p_{20} = 76.1836218495525$$
$$p_{21} = 44.7676953136546$$
$$p_{22} = -62.0464549083984$$
$$p_{23} = 32.2013246992954$$
$$p_{24} = 62.0464549083984$$
$$p_{25} = -33.7721210260903$$
$$p_{26} = 88.7499924639117$$
$$p_{27} = 52.621676947629$$
$$p_{28} = -63.6172512351933$$
$$p_{29} = -16.4933614313464$$
$$p_{30} = -10.2101761241668$$
$$p_{31} = -24.3473430653209$$
$$p_{32} = -47.9092879672443$$
$$p_{33} = -12461.9126586273$$
$$p_{34} = 85.6083998103219$$
$$p_{35} = 10.2101761241668$$
$$p_{36} = 41.6261026600648$$
$$p_{37} = 99.7455667514759$$
$$p_{38} = -5.49778714378214$$
$$p_{39} = 24.3473430653209$$
$$p_{40} = -82.4668071567321$$
$$p_{41} = -76.1836218495525$$
$$p_{42} = 22.776546738526$$
$$p_{43} = -60.4756585816035$$
$$p_{44} = -93.4623814442964$$
$$p_{45} = -57.3340659280137$$
$$p_{46} = 82.4668071567321$$
$$p_{47} = 98.174770424681$$
$$p_{48} = 8.63937979737193$$
$$p_{49} = -54.1924732744239$$
$$p_{50} = -35.3429173528852$$
$$p_{51} = -98.174770424681$$
$$p_{52} = 38.484510006475$$
$$p_{53} = 162.577419823272$$
$$p_{54} = -49.4800842940392$$
$$p_{55} = 49.4800842940392$$
$$p_{56} = -27.4889357189107$$
$$p_{57} = 27.4889357189107$$
$$p_{58} = 1973.70558461779$$
$$p_{59} = -84.037603483527$$
$$p_{60} = 19.6349540849362$$
$$p_{61} = -41.6261026600648$$
$$p_{62} = -91.8915851175014$$
$$p_{63} = 77.7544181763474$$
$$p_{64} = 60.4756585816035$$
$$p_{65} = 25.9181393921158$$
$$p_{66} = -90.3207887907066$$
$$p_{67} = -55.7632696012188$$
$$p_{68} = -19.6349540849362$$
$$p_{69} = -13.3517687777566$$
$$p_{70} = 66.7588438887831$$
$$p_{71} = 91.8915851175014$$
$$p_{72} = -3.92699081698724$$
$$p_{73} = -77.7544181763474$$
$$p_{74} = 63.6172512351933$$
$$p_{75} = -79.3252145031423$$
$$p_{76} = 90.3207887907066$$
$$p_{77} = -40.0553063332699$$
$$p_{78} = 30.6305283725005$$
$$p_{79} = 3.92699081698724$$
$$p_{80} = 69.9004365423729$$
$$p_{81} = 54.1924732744239$$
$$p_{82} = 87.1791961371168$$
$$p_{83} = -46.3384916404494$$
$$p_{84} = 84.037603483527$$
$$p_{85} = 68.329640215578$$
$$p_{86} = 74.6128255227576$$
$$p_{87} = -71.4712328691678$$
$$p_{88} = -2.35619449019234$$
$$p_{89} = -99.7455667514759$$
$$p_{90} = 16.4933614313464$$