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$$- \frac{3 x \cos{\left(x \right)}}{\sin^{2}{\left(x \right)}} + \frac{3}{\sin{\left(x \right)}} = 0$$
Resolvermos esta ecuaciónRaíces de esta ecuación
$$x_{1} = 20.3713029592876$$
$$x_{2} = -4.49340945790906$$
$$x_{3} = -7.72525183693771$$
$$x_{4} = -42.3879135681319$$
$$x_{5} = -67.5294347771441$$
$$x_{6} = -73.8138806006806$$
$$x_{7} = 70.6716857116195$$
$$x_{8} = -92.6661922776228$$
$$x_{9} = -95.8081387868617$$
$$x_{10} = 10.9041216594289$$
$$x_{11} = 26.6660542588127$$
$$x_{12} = -10.9041216594289$$
$$x_{13} = 80.0981286289451$$
$$x_{14} = -36.1006222443756$$
$$x_{15} = 83.2401924707234$$
$$x_{16} = -6.16394430836516 \cdot 10^{-17}$$
$$x_{17} = 48.6741442319544$$
$$x_{18} = -14.0661939128315$$
$$x_{19} = 14.0661939128315$$
$$x_{20} = -29.811598790893$$
$$x_{21} = 23.519452498689$$
$$x_{22} = 76.9560263103312$$
$$x_{23} = 67.5294347771441$$
$$x_{24} = -17.2207552719308$$
$$x_{25} = 39.2444323611642$$
$$x_{26} = -23.519452498689$$
$$x_{27} = 17.2207552719308$$
$$x_{28} = 7.56648890999816 \cdot 10^{-17}$$
$$x_{29} = 29.811598790893$$
$$x_{30} = -48.6741442319544$$
$$x_{31} = -86.3822220347287$$
$$x_{32} = 89.5242209304172$$
$$x_{33} = 61.2447302603744$$
$$x_{34} = -39.2444323611642$$
$$x_{35} = -76.9560263103312$$
$$x_{36} = -58.1022547544956$$
$$x_{37} = -54.9596782878889$$
$$x_{38} = 54.9596782878889$$
$$x_{39} = 95.8081387868617$$
$$x_{40} = 92.6661922776228$$
$$x_{41} = -70.6716857116195$$
$$x_{42} = 86.3822220347287$$
$$x_{43} = -26.6660542588127$$
$$x_{44} = -20.3713029592876$$
$$x_{45} = -89.5242209304172$$
$$x_{46} = -83.2401924707234$$
$$x_{47} = 45.5311340139913$$
$$x_{48} = 36.1006222443756$$
$$x_{49} = 4.49340945790906$$
$$x_{50} = -32.9563890398225$$
$$x_{51} = 7.72525183693771$$
$$x_{52} = 98.9500628243319$$
$$x_{53} = -98.9500628243319$$
$$x_{54} = -61.2447302603744$$
$$x_{55} = 42.3879135681319$$
$$x_{56} = 51.8169824872797$$
$$x_{57} = -51.8169824872797$$
$$x_{58} = -80.0981286289451$$
$$x_{59} = 58.1022547544956$$
$$x_{60} = 32.9563890398225$$
$$x_{61} = 64.3871195905574$$
$$x_{62} = -45.5311340139913$$
$$x_{63} = -64.3871195905574$$
$$x_{64} = 73.8138806006806$$
Signos de extremos en los puntos:
(20.37130295928756, 61.1874975655297)
(-4.493409457909064, -13.8100165462551)
(-7.725251836937707, 23.3691173024782)
(-42.38791356813192, -127.199123227854)
(-67.52943477714412, -202.610515649818)
(-73.81388060068065, -221.461962250821)
(70.6716857116195, 212.03628098016)
(-92.66619227762284, -278.014763494855)
(-95.8081387868617, 287.440072224147)
(10.904121659428899, -32.8496396094788)
(26.666054258812675, 80.0543943054063)
(-10.904121659428899, -32.8496396094788)
(80.09812862894512, -240.313112186438)
(-36.10062224437561, -108.343409295997)
(83.2401924707234, 249.738596902977)
(-6.163944308365161e-17, 3)
(48.674144231954386, -146.053246627447)
(-14.066193912831473, 42.3050859914076)
(14.066193912831473, 42.3050859914076)
(-29.81159879089296, -89.4850982131804)
(23.519452498689006, -70.6221056932091)
(76.95602631033118, 230.887569759152)
(67.52943477714412, -202.610515649818)
(-17.22075527193077, -51.7492967026759)
(39.24443236116419, 117.771512863468)
(-23.519452498689006, -70.6221056932091)
(17.22075527193077, -51.7492967026759)
(7.566488909998162e-17, 3)
(29.81159879089296, -89.4850982131804)
(-48.674144231954386, -146.053246627447)
(-86.38222203472871, -259.164030206575)
(89.52422093041719, 268.589417510786)
(61.2447302603744, -183.758681052064)
(-39.24443236116419, 117.771512863468)
(-76.95602631033118, 230.887569759152)
(-58.10225475449559, 174.332578905971)
(-54.959678287888934, -164.906325341311)
(54.959678287888934, -164.906325341311)
(95.8081387868617, 287.440072224147)
(92.66619227762284, -278.014763494855)
(-70.6716857116195, 212.03628098016)
(86.38222203472871, -259.164030206575)
(-26.666054258812675, 80.0543943054063)
(-20.37130295928756, 61.1874975655297)
(-89.52422093041719, 268.589417510786)
(-83.2401924707234, 249.738596902977)
(45.53113401399128, 136.626342560285)
(36.10062224437561, -108.343409295997)
(4.493409457909064, -13.8100165462551)
(-32.956389039822476, 98.9146713430175)
(7.725251836937707, 23.3691173024782)
(98.95006282433188, -296.865347247625)
(-98.95006282433188, -296.865347247625)
(-61.2447302603744, -183.758681052064)
(42.38791356813192, -127.199123227854)
(51.81698248727967, 155.479892805415)
(-51.81698248727967, 155.479892805415)
(-80.09812862894512, -240.313112186438)
(58.10225475449559, 174.332578905971)
(32.956389039822476, 98.9146713430175)
(64.38711959055742, 193.184653951909)
(-45.53113401399128, 136.626342560285)
(-64.38711959055742, 193.184653951909)
(73.81388060068065, -221.461962250821)
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:
$$x_{1} = 20.3713029592876$$
$$x_{2} = -7.72525183693771$$
$$x_{3} = 70.6716857116195$$
$$x_{4} = -95.8081387868617$$
$$x_{5} = 26.6660542588127$$
$$x_{6} = 83.2401924707234$$
$$x_{7} = -6.16394430836516 \cdot 10^{-17}$$
$$x_{8} = -14.0661939128315$$
$$x_{9} = 14.0661939128315$$
$$x_{10} = 76.9560263103312$$
$$x_{11} = 39.2444323611642$$
$$x_{12} = 7.56648890999816 \cdot 10^{-17}$$
$$x_{13} = 89.5242209304172$$
$$x_{14} = -39.2444323611642$$
$$x_{15} = -76.9560263103312$$
$$x_{16} = -58.1022547544956$$
$$x_{17} = 95.8081387868617$$
$$x_{18} = -70.6716857116195$$
$$x_{19} = -26.6660542588127$$
$$x_{20} = -20.3713029592876$$
$$x_{21} = -89.5242209304172$$
$$x_{22} = -83.2401924707234$$
$$x_{23} = 45.5311340139913$$
$$x_{24} = -32.9563890398225$$
$$x_{25} = 7.72525183693771$$
$$x_{26} = 51.8169824872797$$
$$x_{27} = -51.8169824872797$$
$$x_{28} = 58.1022547544956$$
$$x_{29} = 32.9563890398225$$
$$x_{30} = 64.3871195905574$$
$$x_{31} = -45.5311340139913$$
$$x_{32} = -64.3871195905574$$
Puntos máximos de la función:
$$x_{32} = -4.49340945790906$$
$$x_{32} = -42.3879135681319$$
$$x_{32} = -67.5294347771441$$
$$x_{32} = -73.8138806006806$$
$$x_{32} = -92.6661922776228$$
$$x_{32} = 10.9041216594289$$
$$x_{32} = -10.9041216594289$$
$$x_{32} = 80.0981286289451$$
$$x_{32} = -36.1006222443756$$
$$x_{32} = 48.6741442319544$$
$$x_{32} = -29.811598790893$$
$$x_{32} = 23.519452498689$$
$$x_{32} = 67.5294347771441$$
$$x_{32} = -17.2207552719308$$
$$x_{32} = -23.519452498689$$
$$x_{32} = 17.2207552719308$$
$$x_{32} = 29.811598790893$$
$$x_{32} = -48.6741442319544$$
$$x_{32} = -86.3822220347287$$
$$x_{32} = 61.2447302603744$$
$$x_{32} = -54.9596782878889$$
$$x_{32} = 54.9596782878889$$
$$x_{32} = 92.6661922776228$$
$$x_{32} = 86.3822220347287$$
$$x_{32} = 36.1006222443756$$
$$x_{32} = 4.49340945790906$$
$$x_{32} = 98.9500628243319$$
$$x_{32} = -98.9500628243319$$
$$x_{32} = -61.2447302603744$$
$$x_{32} = 42.3879135681319$$
$$x_{32} = -80.0981286289451$$
$$x_{32} = 73.8138806006806$$
Decrece en los intervalos
$$\left[95.8081387868617, \infty\right)$$
Crece en los intervalos
$$\left(-\infty, -95.8081387868617\right]$$