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$$- \frac{2 x \cos{\left(x + 4 x \right)}}{\left(x^{2} - 1\right)^{2}} - \frac{5 \sin{\left(x + 4 x \right)}}{x^{2} - 1} = 0$$
Resolvermos esta ecuaciónRaíces de esta ecuación
$$x_{1} = 43.9804772707051$$
$$x_{2} = -43.9804772707051$$
$$x_{3} = -39.5820450949106$$
$$x_{4} = -69.7422096048752$$
$$x_{5} = -47.7505322647089$$
$$x_{6} = -89.8486594021155$$
$$x_{7} = 60.9455844986464$$
$$x_{8} = -27.6431177325273$$
$$x_{9} = 96.1319029246777$$
$$x_{10} = -10.0450569900272$$
$$x_{11} = 10.0450569900272$$
$$x_{12} = 77.9104708292441$$
$$x_{13} = -77.9104708292441$$
$$x_{14} = -59.688919779734$$
$$x_{15} = -5.64024876457399$$
$$x_{16} = -56.5472525996449$$
$$x_{17} = -76.0254897658437$$
$$x_{18} = -54.0339126098678$$
$$x_{19} = 45.8655077270332$$
$$x_{20} = 65.9722328301909$$
$$x_{21} = 55.91891815781$$
$$x_{22} = -93.6186064536815$$
$$x_{23} = -25.7579494846518$$
$$x_{24} = -52.7772402600661$$
$$x_{25} = -86.0787092076392$$
$$x_{26} = 70.3705383836538$$
$$x_{27} = -23.8727474905771$$
$$x_{28} = -79.795450688682$$
$$x_{29} = 72.2555236499826$$
$$x_{30} = -3.74702407259747$$
$$x_{31} = -49.6355515592029$$
$$x_{32} = -74.140507406587$$
$$x_{33} = -21.3590767768119$$
$$x_{34} = 28.271500822307$$
$$x_{35} = 52.1489034467125$$
$$x_{36} = -98.016874525578$$
$$x_{37} = -20.1022039761978$$
$$x_{38} = -32.0417460195949$$
$$x_{39} = 84.1937327998049$$
$$x_{40} = 54.0339126098678$$
$$x_{41} = 64.0872415470646$$
$$x_{42} = 3.74702407259747$$
$$x_{43} = 26.3863422909371$$
$$x_{44} = 0$$
$$x_{45} = 32.0417460195949$$
$$x_{46} = 8.15819343440073$$
$$x_{47} = 42.0954400989517$$
$$x_{48} = -81.680429427562$$
$$x_{49} = 38.3253416359477$$
$$x_{50} = 16.3313658042246$$
$$x_{51} = 23.8727474905771$$
$$x_{52} = 62.2022480991767$$
$$x_{53} = -65.9722328301909$$
$$x_{54} = 74.140507406587$$
$$x_{55} = 11.931302161923$$
$$x_{56} = 98.6451982565458$$
$$x_{57} = -45.8655077270332$$
$$x_{58} = -57.8039204446587$$
$$x_{59} = 76.0254897658437$$
$$x_{60} = 86.0787092076392$$
$$x_{61} = 40.2103952651705$$
$$x_{62} = 89.2203345987252$$
$$x_{63} = 18.2168332867871$$
$$x_{64} = -42.0954400989517$$
$$x_{65} = -37.6969882430057$$
$$x_{66} = 21.9875030069394$$
$$x_{67} = 82.3087554381567$$
$$x_{68} = 6.27011200881177$$
$$x_{69} = -13.8171889415972$$
$$x_{70} = -8.78724240122631$$
$$x_{71} = 50.2638902610058$$
$$x_{72} = 30.1566338943204$$
$$x_{73} = 94.2469306832098$$
$$x_{74} = -99.9018455221845$$
$$x_{75} = -55.91891815781$$
$$x_{76} = 246.928858587175$$
$$x_{77} = -87.9636847230099$$
$$x_{78} = -11.931302161923$$
$$x_{79} = -67.8572221291202$$
$$x_{80} = 87.9636847230099$$
$$x_{81} = -21.9875030069394$$
$$x_{82} = -1.82420087382986$$
$$x_{83} = -33.9268407028905$$
$$x_{84} = -35.8119207078091$$
$$x_{85} = 20.1022039761978$$
$$x_{86} = 98.016874525578$$
$$x_{87} = -91.7336332965327$$
$$x_{88} = 60.3172522833615$$
$$x_{89} = -31.413377404844$$
$$x_{90} = -71.6271954015107$$
$$x_{91} = 92.3619577619375$$
$$x_{92} = 4.37901497732045$$
$$x_{93} = -96.1319029246777$$
$$x_{94} = -64.0872415470646$$
$$x_{95} = 48.3788725817987$$
$$x_{96} = -15.7028490207672$$
$$x_{97} = 33.9268407028905$$
$$x_{98} = 99.9018455221845$$
Signos de extremos en los puntos:
(43.9804772707051, 0.000517233597437444)
(-43.9804772707051, 0.000517233597437444)
(-39.58204509491064, -0.00063864368718547)
(-69.74220960487521, -0.00020563202187301)
(-47.750532264708944, 0.000438751715954693)
(-89.84865940211554, -0.000123887158728359)
(60.94558449864636, -0.000269291773823358)
(-27.643117732527344, 0.00131023466726553)
(96.13190292467768, -0.000108220156705173)
(-10.0450569900272, 0.0100016064521053)
(10.0450569900272, 0.0100016064521053)
(77.91047082924406, 0.000164768493052767)
(-77.91047082924406, 0.000164768493052767)
(-59.688919779734, -0.000280753202870758)
(-5.640248764573985, -0.0323678101092314)
(-56.54725259964493, 0.000312825357865791)
(-76.02548976584366, -0.000173041662620807)
(-54.03391260986782, 0.000342613154727243)
(45.86550772703323, -0.000475573400322225)
(65.97223283019088, -0.000229810275503831)
(55.91891815780999, -0.000319897076825524)
(-93.61860645368154, -0.000114109353609796)
(-25.75794948465181, -0.00150931531853117)
(-52.77724026006608, 0.000359128695556195)
(-86.07870920763919, -0.000134977827793602)
(70.37053838365381, 0.000201975616905833)
(-23.872747490577076, 0.00175750566782006)
(-79.79545068868202, -0.000157074790825559)
(72.25552364998259, -0.000191573057061236)
(-3.7470240725974677, 0.0761844297909742)
(-49.635551559202874, -0.000406047177822934)
(-74.14050740658705, 0.000181953990540541)
(-21.359076776811886, 0.00219640070375977)
(28.27150082230704, -0.0012525711293605)
(52.148903446712495, -0.00036783798851984)
(-98.01687452557796, 0.000104097401776241)
(-20.102203976197767, 0.00248028917179634)
(-32.04174601959489, -0.000974893031047041)
(84.19373279980488, 0.000141090196683047)
(54.03391260986782, 0.000342613154727243)
(64.08724154706462, 0.000243530932716317)
(3.7470240725974677, 0.0761844297909742)
(26.386342290937076, 0.00143818845103276)
(0, -1)
(32.04174601959489, -0.000974893031047041)
(8.158193434400726, -0.0152352419958773)
(42.0954400989517, -0.000564618905910019)
(-81.68042942756199, 0.000149907674194891)
(38.3253416359477, -0.000681239810536001)
(16.33136580422461, 0.00376231502619645)
(23.872747490577076, 0.00175750566782006)
(62.20224809917666, -0.000258518194649307)
(-65.97223283019088, -0.000229810275503831)
(74.14050740658705, 0.000181953990540541)
(11.931302161923014, -0.00707030999095896)
(98.64519825654583, -0.000102775396689447)
(-45.86550772703323, -0.000475573400322225)
(-57.80392044465874, 0.000299367743549506)
(76.02548976584366, -0.000173041662620807)
(86.07870920763919, -0.000134977827793602)
(40.21039526517046, 0.000618828755412424)
(89.22033459872519, 0.000125638429866559)
(18.216833286787086, -0.0030217574355397)
(-42.0954400989517, -0.000564618905910019)
(-37.69698824300569, 0.000704154452351808)
(21.987503006939445, -0.00207240808303087)
(82.30875543815671, -0.000147627379267843)
(6.270112008811766, 0.0260441728434178)
(-13.817188941597209, 0.00526329323148144)
(-8.787242401226308, 0.0131067378246422)
(50.26389026100576, 0.000395955129155678)
(30.156633894320375, 0.00110071225151677)
(94.24693068320978, 0.000112592782692442)
(-99.90184552218453, -0.000100205835347264)
(-55.91891815780999, -0.000319897076825524)
(246.92885858717477, -1.64007177650704e-5)
(-87.9636847230099, 0.00012925424447455)
(-11.931302161923014, -0.00707030999095896)
(-67.85722212912023, 0.000217217407091631)
(87.9636847230099, 0.00012925424447455)
(-21.987503006939445, -0.00207240808303087)
(-1.824200873829856, -0.409937233429038)
(-33.92684070289054, 0.000869481605881122)
(-35.81192070780913, -0.000780290654154347)
(20.102203976197767, 0.00248028917179634)
(98.01687452557796, 0.000104097401776241)
(-91.7336332965327, 0.000118847566237247)
(60.31725228336151, 0.000274932913719903)
(-31.413377404843953, 0.00101432186168238)
(-71.62719540151069, 0.000194949439564309)
(92.36195776193752, -0.000117235888417475)
(4.379014977320452, -0.0547645768509519)
(-96.13190292467768, -0.000108220156705173)
(-64.08724154706462, 0.000243530932716317)
(48.37887258179868, -0.000427424341602152)
(-15.702849020767196, -0.00407067042074794)
(33.92684070289054, 0.000869481605881122)
(99.90184552218453, -0.000100205835347264)
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:
$$x_{1} = -39.5820450949106$$
$$x_{2} = -69.7422096048752$$
$$x_{3} = -89.8486594021155$$
$$x_{4} = 60.9455844986464$$
$$x_{5} = 96.1319029246777$$
$$x_{6} = -59.688919779734$$
$$x_{7} = -5.64024876457399$$
$$x_{8} = -76.0254897658437$$
$$x_{9} = 45.8655077270332$$
$$x_{10} = 65.9722328301909$$
$$x_{11} = 55.91891815781$$
$$x_{12} = -93.6186064536815$$
$$x_{13} = -25.7579494846518$$
$$x_{14} = -86.0787092076392$$
$$x_{15} = -79.795450688682$$
$$x_{16} = 72.2555236499826$$
$$x_{17} = -49.6355515592029$$
$$x_{18} = 28.271500822307$$
$$x_{19} = 52.1489034467125$$
$$x_{20} = -32.0417460195949$$
$$x_{21} = 0$$
$$x_{22} = 32.0417460195949$$
$$x_{23} = 8.15819343440073$$
$$x_{24} = 42.0954400989517$$
$$x_{25} = 38.3253416359477$$
$$x_{26} = 62.2022480991767$$
$$x_{27} = -65.9722328301909$$
$$x_{28} = 11.931302161923$$
$$x_{29} = 98.6451982565458$$
$$x_{30} = -45.8655077270332$$
$$x_{31} = 76.0254897658437$$
$$x_{32} = 86.0787092076392$$
$$x_{33} = 18.2168332867871$$
$$x_{34} = -42.0954400989517$$
$$x_{35} = 21.9875030069394$$
$$x_{36} = 82.3087554381567$$
$$x_{37} = -99.9018455221845$$
$$x_{38} = -55.91891815781$$
$$x_{39} = 246.928858587175$$
$$x_{40} = -11.931302161923$$
$$x_{41} = -21.9875030069394$$
$$x_{42} = -1.82420087382986$$
$$x_{43} = -35.8119207078091$$
$$x_{44} = 92.3619577619375$$
$$x_{45} = 4.37901497732045$$
$$x_{46} = -96.1319029246777$$
$$x_{47} = 48.3788725817987$$
$$x_{48} = -15.7028490207672$$
$$x_{49} = 99.9018455221845$$
Puntos máximos de la función:
$$x_{49} = 43.9804772707051$$
$$x_{49} = -43.9804772707051$$
$$x_{49} = -47.7505322647089$$
$$x_{49} = -27.6431177325273$$
$$x_{49} = -10.0450569900272$$
$$x_{49} = 10.0450569900272$$
$$x_{49} = 77.9104708292441$$
$$x_{49} = -77.9104708292441$$
$$x_{49} = -56.5472525996449$$
$$x_{49} = -54.0339126098678$$
$$x_{49} = -52.7772402600661$$
$$x_{49} = 70.3705383836538$$
$$x_{49} = -23.8727474905771$$
$$x_{49} = -3.74702407259747$$
$$x_{49} = -74.140507406587$$
$$x_{49} = -21.3590767768119$$
$$x_{49} = -98.016874525578$$
$$x_{49} = -20.1022039761978$$
$$x_{49} = 84.1937327998049$$
$$x_{49} = 54.0339126098678$$
$$x_{49} = 64.0872415470646$$
$$x_{49} = 3.74702407259747$$
$$x_{49} = 26.3863422909371$$
$$x_{49} = -81.680429427562$$
$$x_{49} = 16.3313658042246$$
$$x_{49} = 23.8727474905771$$
$$x_{49} = 74.140507406587$$
$$x_{49} = -57.8039204446587$$
$$x_{49} = 40.2103952651705$$
$$x_{49} = 89.2203345987252$$
$$x_{49} = -37.6969882430057$$
$$x_{49} = 6.27011200881177$$
$$x_{49} = -13.8171889415972$$
$$x_{49} = -8.78724240122631$$
$$x_{49} = 50.2638902610058$$
$$x_{49} = 30.1566338943204$$
$$x_{49} = 94.2469306832098$$
$$x_{49} = -87.9636847230099$$
$$x_{49} = -67.8572221291202$$
$$x_{49} = 87.9636847230099$$
$$x_{49} = -33.9268407028905$$
$$x_{49} = 20.1022039761978$$
$$x_{49} = 98.016874525578$$
$$x_{49} = -91.7336332965327$$
$$x_{49} = 60.3172522833615$$
$$x_{49} = -31.413377404844$$
$$x_{49} = -71.6271954015107$$
$$x_{49} = -64.0872415470646$$
$$x_{49} = 33.9268407028905$$
Decrece en los intervalos
$$\left[246.928858587175, \infty\right)$$
Crece en los intervalos
$$\left(-\infty, -99.9018455221845\right]$$