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$$x \cos{\left(x \right)} - \sin{\left(x \right)} - \frac{2 \cos{\left(x \right)}}{x} + \frac{2 \sin{\left(x \right)}}{x^{2}} + \frac{1}{x^{2}} = 0$$
Resolvermos esta ecuaciónRaíces de esta ecuación
$$x_{1} = -14.0658299884284$$
$$x_{2} = 67.5294315280758$$
$$x_{3} = -58.1022496524676$$
$$x_{4} = -20.3711839524432$$
$$x_{5} = 4.48076139983567$$
$$x_{6} = -7.7229868515761$$
$$x_{7} = -29.8116366408311$$
$$x_{8} = 20.3714219619473$$
$$x_{9} = 51.8169896815697$$
$$x_{10} = 48.674135551076$$
$$x_{11} = -26.6660013345631$$
$$x_{12} = -92.6661935347016$$
$$x_{13} = -48.6741529128235$$
$$x_{14} = 70.6716885461492$$
$$x_{15} = 86.3822204827976$$
$$x_{16} = 32.9564170412594$$
$$x_{17} = -80.0981305756589$$
$$x_{18} = 39.2444489329984$$
$$x_{19} = -39.2444157892879$$
$$x_{20} = 98.950061791897$$
$$x_{21} = 58.1022598565209$$
$$x_{22} = -23.5195297097203$$
$$x_{23} = 26.6661071824308$$
$$x_{24} = -61.244734616328$$
$$x_{25} = 83.2401942051561$$
$$x_{26} = -10.9049092832045$$
$$x_{27} = 42.3879004195534$$
$$x_{28} = -45.5311234068389$$
$$x_{29} = -83.2401907362905$$
$$x_{30} = -36.1006435399183$$
$$x_{31} = -98.9500638567667$$
$$x_{32} = -89.5242195362532$$
$$x_{33} = 89.524222324581$$
$$x_{34} = 7.72751275304803$$
$$x_{35} = 92.666191020544$$
$$x_{36} = 10.9033336902598$$
$$x_{37} = 1.68594287551067$$
$$x_{38} = 23.5193752861332$$
$$x_{39} = -54.9596843166329$$
$$x_{40} = 76.9560285054368$$
$$x_{41} = 95.808139924256$$
$$x_{42} = -86.3822235866596$$
$$x_{43} = 205.769458925913$$
$$x_{44} = 64.3871233391209$$
$$x_{45} = -4.50583230072247$$
$$x_{46} = 80.098126682231$$
$$x_{47} = -64.3871158419926$$
$$x_{48} = -95.8081376494673$$
$$x_{49} = -42.3879267166859$$
$$x_{50} = 73.8138781130538$$
$$x_{51} = 54.959672259141$$
$$x_{52} = 45.5311446211289$$
$$x_{53} = 61.244725904419$$
$$x_{54} = -17.2209527406322$$
$$x_{55} = -32.9563610382427$$
$$x_{56} = 36.1006009487575$$
$$x_{57} = -51.8169752929837$$
$$x_{58} = 29.8115609406661$$
$$x_{59} = -70.6716828770891$$
$$x_{60} = 17.2205577895808$$
$$x_{61} = -76.9560241152252$$
$$x_{62} = -67.5294380262115$$
$$x_{63} = 14.0665577803655$$
$$x_{64} = -73.813883088307$$
Signos de extremos en los puntos:
(-14.065829988428435, 14.1018752273467)
(67.5294315280758, -67.5368401736719)
(-58.10224965246758, 58.1108621846378)
(-20.37118395244317, 20.3958917029457)
(4.480761399835674, -4.60896622529883)
(-7.722986851576098, 7.79079580643814)
(-29.81163664083107, -29.7612969663847)
(20.371421961947284, 20.297714379478)
(51.81698968156966, 51.7880371447086)
(48.674135551076034, -48.6844198788001)
(-26.666001334563102, 26.6848244802406)
(-92.66619353470156, -92.650005615691)
(-48.67415291282345, -48.6433303017452)
(70.67168854614921, 70.650461866531)
(86.38222048279765, -86.3880108445899)
(32.95641704125936, 32.9108848259514)
(-80.09813057565891, -80.0794023294567)
(39.244448932998445, 39.2062165852274)
(-39.24441578928791, 39.2571792283253)
(98.95006179189696, -98.9551162653072)
(58.10225985652092, 58.0764401125779)
(-23.519529709720253, -23.4557043540075)
(26.66610718243083, 26.6098227578035)
(-61.24473461632797, -61.2202399898692)
(83.24019420515613, 83.2221729800104)
(-10.904909283204516, -10.7668495380198)
(42.387900419553446, -42.3997143086762)
(-45.531123406838866, 45.5421194845827)
(-83.24019073629047, 83.2461998345939)
(-36.10064353991828, -36.0590796876388)
(-98.95006385676675, -98.934904049742)
(-89.52421953625323, 89.529806533815)
(89.52422232458102, 89.507466210948)
(7.72751275304803, 7.53190453984876)
(92.666191020544, -92.6715884599932)
(10.903333690259798, -10.9502664216997)
(1.6859428755106693, -0.326570170529695)
(23.519375286133215, -23.540740347092)
(-54.95968431663294, -54.9323878109937)
(76.95602850543676, 76.9365354823114)
(95.80813992425604, 95.792482923346)
(-86.38222358665962, -86.3648579324178)
(205.76945892591286, -205.771888987586)
(64.3871233391209, 64.3638244106602)
(-4.50583230072247, -4.16386503618429)
(80.09812668223103, -80.1043717018282)
(-64.38711584199261, 64.3948865239015)
(-95.80813764946727, 95.8133579766069)
(-42.387926716685904, -42.3525310474198)
(73.81387811305383, -73.8206553269066)
(54.959672259140966, -54.9687781258992)
(45.53114462112886, 45.4981934976001)
(61.24472590441898, -61.2528958606927)
(-17.220952740632157, -17.1337246357965)
(-32.956361038242676, 32.9715710861355)
(36.10060094875749, -36.114480394764)
(-51.816975292983685, 51.8266345292725)
(29.81156094066608, -29.8283849482817)
(-70.67168287708911, 70.6787617433467)
(17.220557789580813, -17.2498635605283)
(-76.95602411522523, 76.9625243501868)
(-67.5294380262115, -67.507223459026)
(14.066557780365502, 13.95969035387)
(-73.81388308830695, -73.7935601520733)
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:
$$x_{1} = 67.5294315280758$$
$$x_{2} = 4.48076139983567$$
$$x_{3} = -29.8116366408311$$
$$x_{4} = 48.674135551076$$
$$x_{5} = -92.6661935347016$$
$$x_{6} = -48.6741529128235$$
$$x_{7} = 86.3822204827976$$
$$x_{8} = -80.0981305756589$$
$$x_{9} = 98.950061791897$$
$$x_{10} = -23.5195297097203$$
$$x_{11} = -61.244734616328$$
$$x_{12} = -10.9049092832045$$
$$x_{13} = 42.3879004195534$$
$$x_{14} = -36.1006435399183$$
$$x_{15} = -98.9500638567667$$
$$x_{16} = 92.666191020544$$
$$x_{17} = 10.9033336902598$$
$$x_{18} = 23.5193752861332$$
$$x_{19} = -54.9596843166329$$
$$x_{20} = -86.3822235866596$$
$$x_{21} = 205.769458925913$$
$$x_{22} = -4.50583230072247$$
$$x_{23} = 80.098126682231$$
$$x_{24} = -42.3879267166859$$
$$x_{25} = 73.8138781130538$$
$$x_{26} = 54.959672259141$$
$$x_{27} = 61.244725904419$$
$$x_{28} = -17.2209527406322$$
$$x_{29} = 36.1006009487575$$
$$x_{30} = 29.8115609406661$$
$$x_{31} = 17.2205577895808$$
$$x_{32} = -67.5294380262115$$
$$x_{33} = -73.813883088307$$
Puntos máximos de la función:
$$x_{33} = -14.0658299884284$$
$$x_{33} = -58.1022496524676$$
$$x_{33} = -20.3711839524432$$
$$x_{33} = -7.7229868515761$$
$$x_{33} = 20.3714219619473$$
$$x_{33} = 51.8169896815697$$
$$x_{33} = -26.6660013345631$$
$$x_{33} = 70.6716885461492$$
$$x_{33} = 32.9564170412594$$
$$x_{33} = 39.2444489329984$$
$$x_{33} = -39.2444157892879$$
$$x_{33} = 58.1022598565209$$
$$x_{33} = 26.6661071824308$$
$$x_{33} = 83.2401942051561$$
$$x_{33} = -45.5311234068389$$
$$x_{33} = -83.2401907362905$$
$$x_{33} = -89.5242195362532$$
$$x_{33} = 89.524222324581$$
$$x_{33} = 7.72751275304803$$
$$x_{33} = 1.68594287551067$$
$$x_{33} = 76.9560285054368$$
$$x_{33} = 95.808139924256$$
$$x_{33} = 64.3871233391209$$
$$x_{33} = -64.3871158419926$$
$$x_{33} = -95.8081376494673$$
$$x_{33} = 45.5311446211289$$
$$x_{33} = -32.9563610382427$$
$$x_{33} = -51.8169752929837$$
$$x_{33} = -70.6716828770891$$
$$x_{33} = -76.9560241152252$$
$$x_{33} = 14.0665577803655$$
Decrece en los intervalos
$$\left[205.769458925913, \infty\right)$$
Crece en los intervalos
$$\left(-\infty, -98.9500638567667\right]$$