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$$3 \frac{1}{2 x} \cos{\left(3 x \right)} - \frac{2 x \left(x - 1\right)}{\left(x^{2} - 4\right)^{2}} + \frac{1}{x^{2} - 4} - \frac{\sin{\left(3 x \right)}}{2 x^{2}} = 0$$
Resolvermos esta ecuaciónRaíces de esta ecuación
$$x_{1} = -21.4739793725166$$
$$x_{2} = 62.3099338592203$$
$$x_{3} = -27.7554476509841$$
$$x_{4} = -91.6260912952803$$
$$x_{5} = -8495.39014716725$$
$$x_{6} = -16.2086080610791$$
$$x_{7} = 53.932597935885$$
$$x_{8} = 64.4042772811497$$
$$x_{9} = -67.5459933026873$$
$$x_{10} = -34.0376393480567$$
$$x_{11} = -43.4507577981096$$
$$x_{12} = 51.8382755576786$$
$$x_{13} = -5.66377961266401$$
$$x_{14} = -56.0189614233548$$
$$x_{15} = -89.5316083266597$$
$$x_{16} = -53.9243220629616$$
$$x_{17} = 86.3899949788424$$
$$x_{18} = 66.4986237979768$$
$$x_{19} = -38.2259712921274$$
$$x_{20} = 71.7284643872573$$
$$x_{21} = 84.2955066914144$$
$$x_{22} = -18.3059450316161$$
$$x_{23} = -71.7346749372935$$
$$x_{24} = 49.7439589271831$$
$$x_{25} = 38.2142459113972$$
$$x_{26} = -184.830982372558$$
$$x_{27} = 82.2010137178493$$
$$x_{28} = -29.8494573795171$$
$$x_{29} = -25.6615132195048$$
$$x_{30} = 78.0120122217482$$
$$x_{31} = 88.4844789091251$$
$$x_{32} = 31.9294426102745$$
$$x_{33} = -12.0101369031188$$
$$x_{34} = -75.9233692564601$$
$$x_{35} = -69.6403323820584$$
$$x_{36} = 12.0503556217359$$
$$x_{37} = 16.2373072260106$$
$$x_{38} = -49.7349794816344$$
$$x_{39} = -95.8150455211189$$
$$x_{40} = 36.1193727823579$$
$$x_{41} = 75.9175028523412$$
$$x_{42} = 40.3090703092807$$
$$x_{43} = 208.916433417059$$
$$x_{44} = 34.0244420673533$$
$$x_{45} = 60.2155938389814$$
$$x_{46} = 93.7253189392189$$
$$x_{47} = 42.4038530963323$$
$$x_{48} = -6.8442016972462$$
$$x_{49} = -100.003985793389$$
$$x_{50} = 9.95756673500463$$
$$x_{51} = -23.5676784432488$$
$$x_{52} = -320.96640001395$$
$$x_{53} = 3.72465876314914$$
$$x_{54} = -36.1317902652531$$
$$x_{55} = 7.86603628726821$$
$$x_{56} = 73.8229870916504$$
$$x_{57} = -97.9095172876736$$
$$x_{58} = 27.7391761293701$$
$$x_{59} = -62.3027782930547$$
$$x_{60} = 58.1212575693941$$
$$x_{61} = 14.1436862283443$$
$$x_{62} = 95.8196901125633$$
$$x_{63} = 44.4986000648908$$
$$x_{64} = 68.5929731388662$$
$$x_{65} = 29.8343601469208$$
$$x_{66} = -31.9435253678456$$
$$x_{67} = -374.372230951242$$
$$x_{68} = -58.1135826616926$$
$$x_{69} = -82.2064300459562$$
$$x_{70} = -73.8290206544931$$
$$x_{71} = 100.008435359475$$
$$x_{72} = 97.9140622726068$$
$$x_{73} = 56.026925449142$$
$$x_{74} = -9.90684805563754$$
$$x_{75} = -93.7205702713482$$
$$x_{76} = 18.3311063703045$$
$$x_{77} = -7.79646958415439$$
$$x_{78} = -45.5455313755881$$
$$x_{79} = 20.4250248320047$$
$$x_{80} = 22.5190281723597$$
$$x_{81} = 91.630948817728$$
$$x_{82} = -14.1102331426194$$
$$x_{83} = -65.4516580560656$$
$$x_{84} = 9287.07144689999$$
$$x_{85} = -47.6402704273772$$
$$x_{86} = -78.0177204974878$$
$$x_{87} = 5.7788018906052$$
$$x_{88} = -51.8296623064097$$
$$x_{89} = -84.3007879836724$$
$$x_{90} = -60.2081877256431$$
$$x_{91} = -80.1120741590105$$
$$x_{92} = 80.1065156951404$$
Signos de extremos en los puntos:
(-21.473979372516613, -0.0258833577183852)
(62.30993385922029, 0.00778322619509438)
(-27.75544765098412, -0.0195091945333374)
(-91.6260912952803, -0.0164949205542315)
(-8495.39014716725, -5.88693112440019e-5)
(-16.20860806107913, -0.0972893685144118)
(53.93259793588496, 0.00895225187409264)
(64.40427728114967, 0.0075372218732648)
(-67.54599330268731, -0.00763482898780914)
(-34.03763934805667, -0.0156584497267228)
(-43.45075779810961, -0.0350982310905786)
(51.83827555767863, 0.00930162503199509)
(-5.663779612664006, -0.321986473907335)
(-56.01896142335479, -0.0271170008964228)
(-89.53160832665971, -0.0168838906553467)
(-53.92432206296164, -0.0281849953646293)
(86.38999497884242, 0.017234890290084)
(66.49862379797683, 0.00730630857246911)
(-38.225971292127404, -0.0138387823909699)
(71.72846438725732, 0.0207278772106654)
(84.29550669141443, 0.0176600086515727)
(-18.3059450316161, -0.0855714815578505)
(-71.73467493729352, -0.00717554103572266)
(49.74395892718314, 0.00967943320418455)
(38.21424591139722, 0.0386333751941908)
(-184.83098237255774, -0.00273508762690104)
(82.20101371784929, 0.0181066371679824)
(-29.849457379517137, -0.0180306221782676)
(-25.661513219504762, -0.0212527857853032)
(78.01201222174818, 0.0190713056842914)
(88.48447890912506, 0.0168297642176638)
(31.92944261027449, 0.0461100390926758)
(-12.01013690311882, -0.134200404556965)
(-75.92336925646015, -0.00676840491806044)
(-69.64033238205843, -0.00739805882234463)
(12.050355621735926, 0.0367723604210944)
(16.237307226010618, 0.027895282996978)
(-49.73497948163444, -0.0305951992568579)
(-95.81504552111886, -0.0157683917696909)
(36.11937278235789, 0.0408402560702292)
(75.9175028523412, 0.0195932575409922)
(40.309070309280735, 0.0366531171939254)
(208.9164334170588, 0.00237082941710456)
(34.02444206735335, 0.0433151130269109)
(60.21559383898144, 0.00804585311187564)
(93.72531893921894, 0.00522573987564745)
(42.40385309633234, 0.0348662327962823)
(-6.844201697246203, -0.110496626300929)
(-100.00398579338876, -0.0151031782262389)
(9.957566735004626, 0.0439444416179827)
(-23.567678443248848, -0.0233398694294342)
(-320.96640001395, -0.00156762457855618)
(3.7246587631491357, 0.14385849613445)
(-36.13179026525313, -0.014692381490361)
(7.866036287268207, 0.0551137316660185)
(73.82298709165045, 0.0201445964052492)
(-97.90951728767358, -0.015428616296855)
(27.73917612937014, 0.0529462923869054)
(-62.30277829305467, -0.0243493361809332)
(58.1212575693941, 0.00832684906723533)
(14.143686228344317, 0.0316999185816176)
(95.81969011256334, 0.00511374883592063)
(44.49860006489079, 0.0332456817464416)
(68.59297313886621, 0.00708913748775013)
(29.83436014692076, 0.0492916066775978)
(-31.943525367845556, -0.0167608285744374)
(-374.3722309512423, -0.00401391405223129)
(-58.11358266169263, -0.0261270431159949)
(-82.20643004595622, -0.00623757174245023)
(-73.82902065449306, -0.00696602568961221)
(100.00843535947489, 0.00490358144209832)
(97.91406227260678, 0.00500645940015039)
(56.026925449142, 0.00862821450183353)
(-9.906848055637544, -0.16592976045388)
(-93.72057027134824, -0.0161234737103264)
(18.33110637030448, 0.0249247096319015)
(-7.7964695841543925, -0.218087899388977)
(-45.54553137558814, -0.0334566698491087)
(20.425024832004656, 0.0225359124294104)
(22.51902817235966, 0.0205706870571991)
(91.63094881772804, 0.00534274867218842)
(-14.110233142619435, -0.112768844529317)
(-65.45165805606563, -0.00788726708402482)
(9287.071446899987, 0.00016150326563976)
(-47.640270427377175, -0.0319619516666842)
(-78.01772049748784, -0.00658169329213978)
(5.7788018906052, 0.0761950080632073)
(-51.82966230640966, -0.0293406406378047)
(-84.30078798367242, -0.00607866743628605)
(-60.20818772564306, -0.0252068652113071)
(-80.11207415901049, -0.0064050113545272)
(80.10651569514039, 0.0185764514089803)
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:
$$x_{1} = 62.3099338592203$$
$$x_{2} = -91.6260912952803$$
$$x_{3} = -16.2086080610791$$
$$x_{4} = 53.932597935885$$
$$x_{5} = 64.4042772811497$$
$$x_{6} = -43.4507577981096$$
$$x_{7} = 51.8382755576786$$
$$x_{8} = -5.66377961266401$$
$$x_{9} = -56.0189614233548$$
$$x_{10} = -89.5316083266597$$
$$x_{11} = -53.9243220629616$$
$$x_{12} = 66.4986237979768$$
$$x_{13} = -18.3059450316161$$
$$x_{14} = 49.7439589271831$$
$$x_{15} = -12.0101369031188$$
$$x_{16} = 12.0503556217359$$
$$x_{17} = 16.2373072260106$$
$$x_{18} = -49.7349794816344$$
$$x_{19} = -95.8150455211189$$
$$x_{20} = 208.916433417059$$
$$x_{21} = 60.2155938389814$$
$$x_{22} = 93.7253189392189$$
$$x_{23} = -100.003985793389$$
$$x_{24} = 9.95756673500463$$
$$x_{25} = 3.72465876314914$$
$$x_{26} = 7.86603628726821$$
$$x_{27} = -97.9095172876736$$
$$x_{28} = -62.3027782930547$$
$$x_{29} = 58.1212575693941$$
$$x_{30} = 14.1436862283443$$
$$x_{31} = 95.8196901125633$$
$$x_{32} = 68.5929731388662$$
$$x_{33} = -374.372230951242$$
$$x_{34} = -58.1135826616926$$
$$x_{35} = 100.008435359475$$
$$x_{36} = 97.9140622726068$$
$$x_{37} = 56.026925449142$$
$$x_{38} = -9.90684805563754$$
$$x_{39} = -93.7205702713482$$
$$x_{40} = 18.3311063703045$$
$$x_{41} = -7.79646958415439$$
$$x_{42} = -45.5455313755881$$
$$x_{43} = 20.4250248320047$$
$$x_{44} = 22.5190281723597$$
$$x_{45} = 91.630948817728$$
$$x_{46} = -14.1102331426194$$
$$x_{47} = -47.6402704273772$$
$$x_{48} = 5.7788018906052$$
$$x_{49} = -51.8296623064097$$
$$x_{50} = -60.2081877256431$$
Puntos máximos de la función:
$$x_{50} = -21.4739793725166$$
$$x_{50} = -27.7554476509841$$
$$x_{50} = -8495.39014716725$$
$$x_{50} = -67.5459933026873$$
$$x_{50} = -34.0376393480567$$
$$x_{50} = 86.3899949788424$$
$$x_{50} = -38.2259712921274$$
$$x_{50} = 71.7284643872573$$
$$x_{50} = 84.2955066914144$$
$$x_{50} = -71.7346749372935$$
$$x_{50} = 38.2142459113972$$
$$x_{50} = -184.830982372558$$
$$x_{50} = 82.2010137178493$$
$$x_{50} = -29.8494573795171$$
$$x_{50} = -25.6615132195048$$
$$x_{50} = 78.0120122217482$$
$$x_{50} = 88.4844789091251$$
$$x_{50} = 31.9294426102745$$
$$x_{50} = -75.9233692564601$$
$$x_{50} = -69.6403323820584$$
$$x_{50} = 36.1193727823579$$
$$x_{50} = 75.9175028523412$$
$$x_{50} = 40.3090703092807$$
$$x_{50} = 34.0244420673533$$
$$x_{50} = 42.4038530963323$$
$$x_{50} = -6.8442016972462$$
$$x_{50} = -23.5676784432488$$
$$x_{50} = -320.96640001395$$
$$x_{50} = -36.1317902652531$$
$$x_{50} = 73.8229870916504$$
$$x_{50} = 27.7391761293701$$
$$x_{50} = 44.4986000648908$$
$$x_{50} = 29.8343601469208$$
$$x_{50} = -31.9435253678456$$
$$x_{50} = -82.2064300459562$$
$$x_{50} = -73.8290206544931$$
$$x_{50} = -65.4516580560656$$
$$x_{50} = 9287.07144689999$$
$$x_{50} = -78.0177204974878$$
$$x_{50} = -84.3007879836724$$
$$x_{50} = -80.1120741590105$$
$$x_{50} = 80.1065156951404$$
Decrece en los intervalos
$$\left[208.916433417059, \infty\right)$$
Crece en los intervalos
$$\left(-\infty, -374.372230951242\right]$$