Para hallar los extremos hay que resolver la ecuación
$$\frac{d}{d x} f{\left(x \right)} = 0$$
(la derivada es igual a cero),
y las raíces de esta ecuación serán los extremos de esta función:
$$\frac{d}{d x} f{\left(x \right)} = $$
primera derivada$$\frac{\frac{2 \sin^{3}{\left(x \right)}}{\cos^{3}{\left(x \right)}} - \frac{2 \sin^{2}{\left(x \right)}}{\cos^{2}{\left(x \right)}} + \frac{2 \sin{\left(x \right)} \cos{\left(x \right)}}{\cos^{2}{\left(x \right)}} - 2}{x^{2}} - \frac{2 \left(\left(\frac{\sin^{2}{\left(x \right)}}{\cos^{2}{\left(x \right)}} + 1\right) - \frac{2 \sin{\left(x \right)}}{\cos{\left(x \right)}}\right)}{x^{3}} = 0$$
Resolvermos esta ecuaciónRaíces de esta ecuación
$$x_{1} = -5.49778714378214$$
$$x_{2} = 73.0420291959627$$
$$x_{3} = -74.6128255227576$$
$$x_{4} = 51.0508806208341$$
$$x_{5} = -46.3384916404494$$
$$x_{6} = -55.7632696012188$$
$$x_{7} = 98.174770424681$$
$$x_{8} = -90.3207887907066$$
$$x_{9} = -68.329640215578$$
$$x_{10} = 44.7676953136546$$
$$x_{11} = 66.7588438887831$$
$$x_{12} = -96.6039740978861$$
$$x_{13} = -18.0641577581413$$
$$x_{14} = -27.4889357189107$$
$$x_{15} = 7.06858347057703$$
$$x_{16} = -11.7809724509617$$
$$x_{17} = -52.621676947629$$
$$x_{18} = 25.9181393921158$$
$$x_{19} = -40.0553063332699$$
$$x_{20} = -87.1791961371168$$
$$x_{21} = 189.280957378785$$
$$x_{22} = 41.6261026600648$$
$$x_{23} = 22.776546738526$$
$$x_{24} = 3.92699081698724$$
$$x_{25} = 91.8915851175014$$
$$x_{26} = 101.316363078271$$
$$x_{27} = -2.35619449019234$$
$$x_{28} = 16.4933614313464$$
$$x_{29} = -30.6305283725005$$
$$x_{30} = 13.3517687777566$$
$$x_{31} = -36.9137136796801$$
$$x_{32} = 82.4668071567321$$
$$x_{33} = -99.7455667514759$$
$$x_{34} = -8.63937979737193$$
$$x_{35} = 10.2101761241668$$
$$x_{36} = -49.4800842940392$$
$$x_{37} = 19.6349540849362$$
$$x_{38} = 95.0331777710912$$
$$x_{39} = 63.6172512351933$$
$$x_{40} = -77.7544181763474$$
$$x_{41} = 54.1924732744239$$
$$x_{42} = -58.9048622548086$$
$$x_{43} = 76.1836218495525$$
$$x_{44} = 69.9004365423729$$
$$x_{45} = 88.7499924639117$$
$$x_{46} = 85.6083998103219$$
$$x_{47} = -14.9225651045515$$
$$x_{48} = 35.3429173528852$$
$$x_{49} = -62.0464549083984$$
$$x_{50} = 57.3340659280137$$
$$x_{51} = 29.0597320457056$$
$$x_{52} = -84.037603483527$$
$$x_{53} = -71.4712328691678$$
$$x_{54} = -24.3473430653209$$
$$x_{55} = -80.8960108299372$$
$$x_{56} = 60.4756585816035$$
$$x_{57} = 38.484510006475$$
$$x_{58} = -93.4623814442964$$
$$x_{59} = 79.3252145031423$$
$$x_{60} = -33.7721210260903$$
$$x_{61} = 32.2013246992954$$
$$x_{62} = 47.9092879672443$$
Signos de extremos en los puntos:
(-5.497787143782138, 0)
(73.0420291959627, 0)
(-74.61282552275759, 0)
(51.05088062083414, 0)
(-46.33849164044945, 0)
(-55.76326960121883, 0)
(98.17477042468104, 4.6075539850034e-20)
(-90.32078879070656, 0)
(-68.329640215578, 0)
(44.767695313654556, 0)
(66.7588438887831, 0)
(-96.60397409788614, 0)
(-18.06415775814131, 0)
(-27.488935718910692, 0)
(7.0685834705770345, 0)
(-11.780972450961725, 1.59984513368174e-18)
(-52.621676947629034, 0)
(25.918139392115794, 0)
(-40.05530633326986, 0)
(-87.17919613711676, 0)
(189.28095737878505, 1.23952809035103e-20)
(41.62610266006476, 1.28147082619577e-19)
(22.776546738526, 0)
(3.9269908169872414, 0)
(91.89158511750145, 0)
(101.31636307827083, 0)
(-2.356194490192345, 0)
(16.493361431346415, 0)
(-30.630528372500486, 2.36663481313867e-19)
(13.351768777756622, 2.49110833964284e-18)
(-36.91371367968007, -1.62953895463282e-19)
(82.46680715673207, 0)
(-99.74556675147593, 0)
(-8.639379797371932, 0)
(10.210176124166829, 0)
(-49.480084294039244, 9.06941685760622e-20)
(19.634954084936208, 0)
(95.03317777109125, 0)
(63.617251235193315, 0)
(-77.75441817634739, 0)
(54.19247327442393, -7.56070479055642e-20)
(-58.90486225480862, 0)
(76.18362184955248, 3.82575358782433e-20)
(69.9004365423729, 9.08888158258783e-20)
(88.74999246391165, 0)
(85.60839981032187, 0)
(-14.922565104551518, 0)
(35.34291735288517, 0)
(-62.04645490839842, 0)
(57.33406592801373, 0)
(29.059732045705587, 0)
(-84.03760348352696, 6.28815014548678e-20)
(-71.47123286916779, 8.6937605380604e-20)
(-24.3473430653209, 0)
(-80.89601082993718, 0)
(60.47565858160352, 6.07126252451326e-20)
(38.48451000647497, 0)
(-93.46238144429635, 0)
(79.32521450314228, 3.52872419447496e-20)
(-33.772121026090275, 0)
(32.201324699295384, 0)
(47.909287967244346, 9.6738821574413e-20)
Intervalos de crecimiento y decrecimiento de la función:Hallemos los intervalos donde la función crece y decrece y también los puntos mínimos y máximos de la función, para lo cual miramos cómo se comporta la función en los extremos con desviación mínima del extremo:
Puntos mínimos de la función:
$$x_{1} = -5.49778714378214$$
$$x_{2} = 73.0420291959627$$
$$x_{3} = -74.6128255227576$$
$$x_{4} = 51.0508806208341$$
$$x_{5} = -46.3384916404494$$
$$x_{6} = -55.7632696012188$$
$$x_{7} = 98.174770424681$$
$$x_{8} = -90.3207887907066$$
$$x_{9} = -68.329640215578$$
$$x_{10} = 44.7676953136546$$
$$x_{11} = 66.7588438887831$$
$$x_{12} = -96.6039740978861$$
$$x_{13} = -18.0641577581413$$
$$x_{14} = -27.4889357189107$$
$$x_{15} = 7.06858347057703$$
$$x_{16} = -11.7809724509617$$
$$x_{17} = -52.621676947629$$
$$x_{18} = 25.9181393921158$$
$$x_{19} = -40.0553063332699$$
$$x_{20} = -87.1791961371168$$
$$x_{21} = 189.280957378785$$
$$x_{22} = 41.6261026600648$$
$$x_{23} = 22.776546738526$$
$$x_{24} = 3.92699081698724$$
$$x_{25} = 91.8915851175014$$
$$x_{26} = 101.316363078271$$
$$x_{27} = -2.35619449019234$$
$$x_{28} = 16.4933614313464$$
$$x_{29} = -30.6305283725005$$
$$x_{30} = 13.3517687777566$$
$$x_{31} = -36.9137136796801$$
$$x_{32} = 82.4668071567321$$
$$x_{33} = -99.7455667514759$$
$$x_{34} = -8.63937979737193$$
$$x_{35} = 10.2101761241668$$
$$x_{36} = -49.4800842940392$$
$$x_{37} = 19.6349540849362$$
$$x_{38} = 95.0331777710912$$
$$x_{39} = 63.6172512351933$$
$$x_{40} = -77.7544181763474$$
$$x_{41} = 54.1924732744239$$
$$x_{42} = -58.9048622548086$$
$$x_{43} = 76.1836218495525$$
$$x_{44} = 69.9004365423729$$
$$x_{45} = 88.7499924639117$$
$$x_{46} = 85.6083998103219$$
$$x_{47} = -14.9225651045515$$
$$x_{48} = 35.3429173528852$$
$$x_{49} = -62.0464549083984$$
$$x_{50} = 57.3340659280137$$
$$x_{51} = 29.0597320457056$$
$$x_{52} = -84.037603483527$$
$$x_{53} = -71.4712328691678$$
$$x_{54} = -24.3473430653209$$
$$x_{55} = -80.8960108299372$$
$$x_{56} = 60.4756585816035$$
$$x_{57} = 38.484510006475$$
$$x_{58} = -93.4623814442964$$
$$x_{59} = 79.3252145031423$$
$$x_{60} = -33.7721210260903$$
$$x_{61} = 32.2013246992954$$
$$x_{62} = 47.9092879672443$$
La función no tiene puntos máximos
Decrece en los intervalos
$$\left[189.280957378785, \infty\right)$$
Crece en los intervalos
$$\left(-\infty, -99.7455667514759\right]$$