El gráfico de la función cruce el eje X con f = 0
o sea hay que resolver la ecuación:
$$\cos^{2}{\left(- 5 x \right)} = 0$$
Resolvermos esta ecuaciónPuntos de cruce con el eje X:
Solución analítica$$x_{1} = \frac{\pi}{10}$$
$$x_{2} = \frac{3 \pi}{10}$$
Solución numérica$$x_{1} = -49.9513232957779$$
$$x_{2} = -48.066367564151$$
$$x_{3} = 70.057516050781$$
$$x_{4} = 60.0044196779815$$
$$x_{5} = 0.31415923359747$$
$$x_{6} = -33.615041292269$$
$$x_{7} = 49.9513232255568$$
$$x_{8} = 61.8893752846508$$
$$x_{9} = -7.85398174607583$$
$$x_{10} = 27.9601746474797$$
$$x_{11} = 90.1637092334337$$
$$x_{12} = 22.3053078107508$$
$$x_{13} = -87.6504350585881$$
$$x_{14} = 92.0486646465177$$
$$x_{15} = 10.367255763258$$
$$x_{16} = 2.19911490270916$$
$$x_{17} = -70.0575161398281$$
$$x_{18} = -41.783182264796$$
$$x_{19} = -39.2699080647417$$
$$x_{20} = 38.0132710898737$$
$$x_{21} = -63.7743308479947$$
$$x_{22} = -81.9955682642931$$
$$x_{23} = 48.066367768388$$
$$x_{24} = 24.1902634867984$$
$$x_{25} = -43.6681379168733$$
$$x_{26} = -38.0132710946769$$
$$x_{27} = -17.2787595616941$$
$$x_{28} = 54.3495528836599$$
$$x_{29} = -4.08407041682777$$
$$x_{30} = 88.2787535473227$$
$$x_{31} = -27.9601746939091$$
$$x_{32} = -36.1283155693936$$
$$x_{33} = -11.623892777114$$
$$x_{34} = -62.5176937985459$$
$$x_{35} = -51.8362787088266$$
$$x_{36} = -93.9336201701711$$
$$x_{37} = 76.3407014529838$$
$$x_{38} = 56.2345085115078$$
$$x_{39} = 100.216805677474$$
$$x_{40} = 71.9424718024321$$
$$x_{41} = 32.3584043192333$$
$$x_{42} = 46.181412070737$$
$$x_{43} = -85.765479430761$$
$$x_{44} = -65.6592864892693$$
$$x_{45} = 16.0221224989335$$
$$x_{46} = -53.7212343949425$$
$$x_{47} = 66.2876049677364$$
$$x_{48} = -92.048664716705$$
$$x_{49} = -21.6769893423933$$
$$x_{50} = -9.73893723394713$$
$$x_{51} = 17.9070781541126$$
$$x_{52} = 83.8805238375842$$
$$x_{53} = -16.0221225125222$$
$$x_{54} = 68.1725606537201$$
$$x_{55} = 44.2964563888458$$
$$x_{56} = -48.0663676902076$$
$$x_{57} = -58.1194641046344$$
$$x_{58} = -29.8451301412989$$
$$x_{59} = 59.3761012681737$$
$$x_{60} = -5.96902609546928$$
$$x_{61} = -98.9601684499278$$
$$x_{62} = 34.2433599291997$$
$$x_{63} = 39.8982267220103$$
$$x_{64} = -14.1371670547755$$
$$x_{65} = 93.9336202505728$$
$$x_{66} = 93.9336203781076$$
$$x_{67} = 78.2256570942747$$
$$x_{68} = -82.6238866510998$$
$$x_{69} = 68.1725607756214$$
$$x_{70} = -19.7920336812043$$
$$x_{71} = -80.1106126575856$$
$$x_{72} = -31.7300858147318$$
$$x_{73} = -71.9424718914835$$
$$x_{74} = -73.8274272885479$$
$$x_{75} = 7.22566302673633$$
$$x_{76} = -97.7035315534175$$
$$x_{77} = -95.8185758715333$$
$$x_{78} = 98.3318500253832$$
$$x_{79} = -75.7123829745279$$
$$x_{80} = 21.0486707779737$$
$$x_{81} = 12.2522113473733$$
$$x_{82} = 5.96902606815067$$
$$x_{83} = 79.4822941438334$$
$$x_{84} = 81.9955682637624$$
$$x_{85} = -60.0044196785094$$
$$x_{86} = -26.0752189897467$$