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$$- \frac{2 \sin{\left(2 x \right)}}{x^{2}} - \frac{2 \left(\cos{\left(2 x \right)} - 1\right)}{x^{3}} = 0$$
Resolvermos esta ecuaciónRaíces de esta ecuación
$$x_{1} = 48.6741442319544$$
$$x_{2} = 34.5575191894877$$
$$x_{3} = -939.336203423348$$
$$x_{4} = -20.3713029592876$$
$$x_{5} = -86.3822220347287$$
$$x_{6} = 67.5294347771441$$
$$x_{7} = -43.9822971502571$$
$$x_{8} = 28.2743338823081$$
$$x_{9} = -39.2444323611642$$
$$x_{10} = 4.49340945790906$$
$$x_{11} = 86.3822220347287$$
$$x_{12} = 58.1022547544956$$
$$x_{13} = -80.0981286289451$$
$$x_{14} = 73.8138806006806$$
$$x_{15} = -12.5663706143592$$
$$x_{16} = 59.6902604182061$$
$$x_{17} = 56.5486677646163$$
$$x_{18} = 100.530964914873$$
$$x_{19} = -54.9596782878889$$
$$x_{20} = 15.707963267949$$
$$x_{21} = -58.1022547544956$$
$$x_{22} = -15.707963267949$$
$$x_{23} = -37.6991118430775$$
$$x_{24} = -29.811598790893$$
$$x_{25} = -51.8169824872797$$
$$x_{26} = 14.0661939128315$$
$$x_{27} = -72.2566310325652$$
$$x_{28} = -36.1006222443756$$
$$x_{29} = -11909.7777497589$$
$$x_{30} = 47.1238898038469$$
$$x_{31} = -89.5242209304172$$
$$x_{32} = 65.9734457253857$$
$$x_{33} = 12.5663706143592$$
$$x_{34} = 21.9911485751286$$
$$x_{35} = -3.14159265358979$$
$$x_{36} = -6.28318530717959$$
$$x_{37} = -65.9734457253857$$
$$x_{38} = 36.1006222443756$$
$$x_{39} = 7.72525183693771$$
$$x_{40} = 81.6814089933346$$
$$x_{41} = 78.5398163397448$$
$$x_{42} = -73.8138806006806$$
$$x_{43} = 23.519452498689$$
$$x_{44} = -67.5294347771441$$
$$x_{45} = -83.2401924707234$$
$$x_{46} = 42.3879135681319$$
$$x_{47} = 51.8169824872797$$
$$x_{48} = -56.5486677646163$$
$$x_{49} = -97.3893722612836$$
$$x_{50} = 37.6991118430775$$
$$x_{51} = -21.9911485751286$$
$$x_{52} = 3.14159265358979$$
$$x_{53} = 69.1150383789755$$
$$x_{54} = 29.811598790893$$
$$x_{55} = -50.2654824574367$$
$$x_{56} = -94.2477796076938$$
$$x_{57} = 80.0981286289451$$
$$x_{58} = -7.72525183693771$$
$$x_{59} = -53.4070751110265$$
$$x_{60} = -61.2447302603744$$
$$x_{61} = 92.6661922776228$$
$$x_{62} = 89.5242209304172$$
$$x_{63} = -42.3879135681319$$
$$x_{64} = -59.6902604182061$$
$$x_{65} = -23.519452498689$$
$$x_{66} = -207.345115136926$$
$$x_{67} = 26.6660542588127$$
$$x_{68} = 20.3713029592876$$
$$x_{69} = -87.9645943005142$$
$$x_{70} = -28.2743338823081$$
$$x_{71} = -95.8081387868617$$
$$x_{72} = 64.3871195905574$$
$$x_{73} = 6.28318530717959$$
$$x_{74} = 70.6716857116195$$
$$x_{75} = 45.5311340139913$$
$$x_{76} = 87.9645943005142$$
$$x_{77} = 43.9822971502571$$
$$x_{78} = 185.353966561798$$
$$x_{79} = -4.49340945790906$$
$$x_{80} = -64.3871195905574$$
$$x_{81} = -75.398223686155$$
$$x_{82} = -9.42477796076938$$
$$x_{83} = -14.0661939128315$$
$$x_{84} = -31.4159265358979$$
$$x_{85} = -45.5311340139913$$
$$x_{86} = 72.2566310325652$$
$$x_{87} = 94.2477796076938$$
$$x_{88} = -100.530964914873$$
$$x_{89} = 95.8081387868617$$
$$x_{90} = -81.6814089933346$$
$$x_{91} = 50.2654824574367$$
Signos de extremos en los puntos:
(48.674144231954386, -0.000843820504482794)
(34.55751918948773, 0)
(-939.3362034233481, 0)
(-20.37130295928756, -0.00480780806192296)
(-86.38222203472871, -0.000267992756153105)
(67.52943477714412, -0.000438478740327786)
(-43.982297150257104, 0)
(28.274333882308138, 0)
(-39.24443236116419, -0.00129775286774544)
(4.493409457909064, -0.0943808984516225)
(86.38222203472871, -0.000267992756153105)
(58.10225475449559, -0.000592264082122352)
(-80.09812862894512, -0.000311686196600725)
(73.81388060068065, -0.00036700689023421)
(-12.566370614359172, 0)
(59.69026041820607, 0)
(56.548667764616276, 0)
(100.53096491487338, 0)
(-54.959678287888934, -0.000661908375587791)
(15.707963267948966, 0)
(-58.10225475449559, -0.000592264082122352)
(-15.707963267948966, 0)
(-37.69911184307752, 0)
(-29.81159879089296, -0.00224786935640603)
(-51.81698248727967, -0.000744601728471834)
(14.066193912831473, -0.0100574374624647)
(-72.25663103256524, 0)
(-36.10062224437561, -0.00153344254981861)
(-11909.777749758907, 0)
(47.1238898038469, 0)
(-89.52422093041719, -0.000249513880428108)
(65.97344572538566, 0)
(12.566370614359172, 0)
(21.991148575128552, 0)
(-3.141592653589793, 0)
(-6.283185307179586, 0)
(-65.97344572538566, 0)
(36.10062224437561, -0.00153344254981861)
(7.725251836937707, -0.0329600519859479)
(81.68140899333463, 0)
(78.53981633974483, 0)
(-73.81388060068065, -0.00036700689023421)
(23.519452498689006, -0.00360903571712935)
(-67.52943477714412, -0.000438478740327786)
(-83.2401924707234, -0.00028860321866995)
(42.38791356813192, -0.00111251088673472)
(51.81698248727967, -0.000744601728471834)
(-56.548667764616276, 0)
(-97.3893722612836, 0)
(37.69911184307752, 0)
(-21.991148575128552, 0)
(3.141592653589793, 0)
(69.11503837897546, 0)
(29.81159879089296, -0.00224786935640603)
(-50.26548245743669, 0)
(-94.2477796076938, 0)
(80.09812862894512, -0.000311686196600725)
(-7.725251836937707, -0.0329600519859479)
(-53.40707511102649, 0)
(-61.2447302603744, -0.000533060834814295)
(92.66619227762284, -0.000232882463806292)
(89.52422093041719, -0.000249513880428108)
(-42.38791356813192, -0.00111251088673472)
(-59.69026041820607, 0)
(-23.519452498689006, -0.00360903571712935)
(-207.34511513692635, 0)
(26.666054258812675, -0.0028086792975511)
(20.37130295928756, -0.00480780806192296)
(-87.96459430051421, 0)
(-28.274333882308138, 0)
(-95.8081387868617, -0.000217860190205359)
(64.38711959055742, -0.000482311099451838)
(6.283185307179586, 0)
(70.6716857116195, -0.000400361353240022)
(45.53113401399128, -0.000964281022986201)
(87.96459430051421, 0)
(43.982297150257104, 0)
(185.3539665617978, 0)
(-4.493409457909064, -0.0943808984516225)
(-64.38711959055742, -0.000482311099451838)
(-75.39822368615503, 0)
(-9.42477796076938, 0)
(-14.066193912831473, -0.0100574374624647)
(-31.41592653589793, 0)
(-45.53113401399128, -0.000964281022986201)
(72.25663103256524, 0)
(94.2477796076938, 0)
(-100.53096491487338, 0)
(95.8081387868617, -0.000217860190205359)
(-81.68140899333463, 0)
(50.26548245743669, 0)
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:
$$x_{1} = 48.6741442319544$$
$$x_{2} = -20.3713029592876$$
$$x_{3} = -86.3822220347287$$
$$x_{4} = 67.5294347771441$$
$$x_{5} = -39.2444323611642$$
$$x_{6} = 4.49340945790906$$
$$x_{7} = 86.3822220347287$$
$$x_{8} = 58.1022547544956$$
$$x_{9} = -80.0981286289451$$
$$x_{10} = 73.8138806006806$$
$$x_{11} = -54.9596782878889$$
$$x_{12} = -58.1022547544956$$
$$x_{13} = -29.811598790893$$
$$x_{14} = -51.8169824872797$$
$$x_{15} = 14.0661939128315$$
$$x_{16} = -36.1006222443756$$
$$x_{17} = -89.5242209304172$$
$$x_{18} = 36.1006222443756$$
$$x_{19} = 7.72525183693771$$
$$x_{20} = -73.8138806006806$$
$$x_{21} = 23.519452498689$$
$$x_{22} = -67.5294347771441$$
$$x_{23} = -83.2401924707234$$
$$x_{24} = 42.3879135681319$$
$$x_{25} = 51.8169824872797$$
$$x_{26} = 29.811598790893$$
$$x_{27} = 80.0981286289451$$
$$x_{28} = -7.72525183693771$$
$$x_{29} = -61.2447302603744$$
$$x_{30} = 92.6661922776228$$
$$x_{31} = 89.5242209304172$$
$$x_{32} = -42.3879135681319$$
$$x_{33} = -23.519452498689$$
$$x_{34} = 26.6660542588127$$
$$x_{35} = 20.3713029592876$$
$$x_{36} = -95.8081387868617$$
$$x_{37} = 64.3871195905574$$
$$x_{38} = 70.6716857116195$$
$$x_{39} = 45.5311340139913$$
$$x_{40} = -4.49340945790906$$
$$x_{41} = -64.3871195905574$$
$$x_{42} = -14.0661939128315$$
$$x_{43} = -45.5311340139913$$
$$x_{44} = 95.8081387868617$$
Puntos máximos de la función:
$$x_{44} = 34.5575191894877$$
$$x_{44} = -939.336203423348$$
$$x_{44} = -43.9822971502571$$
$$x_{44} = 28.2743338823081$$
$$x_{44} = -12.5663706143592$$
$$x_{44} = 59.6902604182061$$
$$x_{44} = 56.5486677646163$$
$$x_{44} = 100.530964914873$$
$$x_{44} = 15.707963267949$$
$$x_{44} = -15.707963267949$$
$$x_{44} = -37.6991118430775$$
$$x_{44} = -72.2566310325652$$
$$x_{44} = -11909.7777497589$$
$$x_{44} = 47.1238898038469$$
$$x_{44} = 65.9734457253857$$
$$x_{44} = 12.5663706143592$$
$$x_{44} = 21.9911485751286$$
$$x_{44} = -3.14159265358979$$
$$x_{44} = -6.28318530717959$$
$$x_{44} = -65.9734457253857$$
$$x_{44} = 81.6814089933346$$
$$x_{44} = 78.5398163397448$$
$$x_{44} = -56.5486677646163$$
$$x_{44} = -97.3893722612836$$
$$x_{44} = 37.6991118430775$$
$$x_{44} = -21.9911485751286$$
$$x_{44} = 3.14159265358979$$
$$x_{44} = 69.1150383789755$$
$$x_{44} = -50.2654824574367$$
$$x_{44} = -94.2477796076938$$
$$x_{44} = -53.4070751110265$$
$$x_{44} = -59.6902604182061$$
$$x_{44} = -207.345115136926$$
$$x_{44} = -87.9645943005142$$
$$x_{44} = -28.2743338823081$$
$$x_{44} = 6.28318530717959$$
$$x_{44} = 87.9645943005142$$
$$x_{44} = 43.9822971502571$$
$$x_{44} = 185.353966561798$$
$$x_{44} = -75.398223686155$$
$$x_{44} = -9.42477796076938$$
$$x_{44} = -31.4159265358979$$
$$x_{44} = 72.2566310325652$$
$$x_{44} = 94.2477796076938$$
$$x_{44} = -100.530964914873$$
$$x_{44} = -81.6814089933346$$
$$x_{44} = 50.2654824574367$$
Decrece en los intervalos
$$\left[95.8081387868617, \infty\right)$$
Crece en los intervalos
$$\left(-\infty, -95.8081387868617\right]$$