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$$\frac{1}{2 x} \left(\cos{\left(x \right)} + 5 \cos{\left(5 x \right)}\right) - \frac{\sin{\left(x \right)} + \sin{\left(5 x \right)}}{2 x^{2}} = 0$$
Resolvermos esta ecuaciónRaíces de esta ecuación
$$x_{1} = -17.9309707406942$$
$$x_{2} = 82.0326913256809$$
$$x_{3} = 66.3245743061849$$
$$x_{4} = -71.9039578993605$$
$$x_{5} = -75.7494521674681$$
$$x_{6} = 5.92222218177546$$
$$x_{7} = 90.1879702595354$$
$$x_{8} = 83.9047781039066$$
$$x_{9} = -114.667461020638$$
$$x_{10} = 61.913594613359$$
$$x_{11} = -43.6291432937174$$
$$x_{12} = -36.1261862516828$$
$$x_{13} = -70.0330458339313$$
$$x_{14} = -63.749848917538$$
$$x_{15} = -14.1317240519071$$
$$x_{16} = 49.912482519663$$
$$x_{17} = -26.0505498058443$$
$$x_{18} = -82.0326913256809$$
$$x_{19} = -31.7661820208789$$
$$x_{20} = 17.9309707406942$$
$$x_{21} = -83.9047781039066$$
$$x_{22} = 78.1872028025887$$
$$x_{23} = -27.9204918749473$$
$$x_{24} = 100.178501077926$$
$$x_{25} = -41.7586321968141$$
$$x_{26} = 70.0330458339313$$
$$x_{27} = 56.1957873110138$$
$$x_{28} = -33.639148765766$$
$$x_{29} = -65.6207015791462$$
$$x_{30} = 68.1967921940531$$
$$x_{31} = 16.0565812988432$$
$$x_{32} = -19.7672638326169$$
$$x_{33} = -87.6120541253982$$
$$x_{34} = 29.1921765407575$$
$$x_{35} = 44.333027533125$$
$$x_{36} = -97.740758937935$$
$$x_{37} = 27.9204918749473$$
$$x_{38} = 26.0505498058443$$
$$x_{39} = -51.8347947877018$$
$$x_{40} = -4.05768431094488$$
$$x_{41} = -60.0413049814727$$
$$x_{42} = 107.165584825836$$
$$x_{43} = 72.6078290944473$$
$$x_{44} = 71.9039578993605$$
$$x_{45} = -93.8952801564952$$
$$x_{46} = -55.6303942603175$$
$$x_{47} = 34.2040283469372$$
$$x_{48} = 54.3250485075438$$
$$x_{49} = -95.8177731298408$$
$$x_{50} = 46.2055860587154$$
$$x_{51} = -76.9680205993594$$
$$x_{52} = -53.7580160254341$$
$$x_{53} = -38.0496439641879$$
$$x_{54} = -9.77127021564343$$
$$x_{55} = -73.8263854165807$$
$$x_{56} = 98.3074135930337$$
$$x_{57} = 294.391556180398$$
$$x_{58} = 36.1261862516828$$
$$x_{59} = -60.6082495566679$$
$$x_{60} = 2.21975854306831$$
$$x_{61} = 39.9223726590362$$
$$x_{62} = 88.3159228235119$$
$$x_{63} = 58.1181405332061$$
$$x_{64} = 7.20016463886828$$
$$x_{65} = -49.912482519663$$
$$x_{66} = -7.84417758696119$$
$$x_{67} = -5.92222218177546$$
$$x_{68} = 65.6207015791462$$
$$x_{69} = 48.0418433405569$$
$$x_{70} = -92.024222556746$$
$$x_{71} = -11.647537375823$$
$$x_{72} = -106.461717794596$$
$$x_{73} = 93.8952801564952$$
$$x_{74} = -39.9223726590362$$
$$x_{75} = -29.8425526210944$$
$$x_{76} = 86.3929075889945$$
$$x_{77} = 12.210066212243$$
$$x_{78} = -58.1181405332061$$
$$x_{79} = 92.024222556746$$
$$x_{80} = -85.7410306807642$$
$$x_{81} = 76.3162408386658$$
$$x_{82} = -61.913594613359$$
$$x_{83} = -16.0565812988432$$
$$x_{84} = 22.3406976411955$$
$$x_{85} = 80.1096524464143$$
$$x_{86} = 32.3337966523473$$
$$x_{87} = 4.05768431094488$$
$$x_{88} = -21.6367512054142$$
$$x_{89} = -48.0418433405569$$
$$x_{90} = -80.1096524464143$$
$$x_{91} = 14.1317240519071$$
$$x_{92} = 38.0496439641879$$
$$x_{93} = 24.2142753830252$$
$$x_{94} = -91.4575361930417$$
$$x_{95} = 43.0639803835175$$
$$x_{96} = 10.342105473901$$
$$x_{97} = 60.0413049814727$$
Signos de extremos en los puntos:
(-17.930970740694246, 0.0055247725811907)
(82.03269132568089, 0.00808778163675302)
(66.3245743061849, -0.0100032470724342)
(-71.90395789936049, 0.00922705396366186)
(-75.74945216746812, 0.00875863814106626)
(5.922222181775459, -0.111944270051768)
(90.18797025953539, -0.00109843647071805)
(83.90477810390662, -0.00118069256826088)
(-114.66746102063841, 0.00872084430902226)
(61.91359461335903, 0.00160006376663961)
(-43.62914329371736, -0.01520671222499)
(-36.12618625168279, -0.0276799362050348)
(-70.03304583393134, -0.00141455682093289)
(-63.74984891753795, -0.00155397553290005)
(-14.131724051907055, 0.0707491488647428)
(49.912482519663, -0.0132924267934124)
(-26.050549805844287, -0.00380280664322429)
(-82.03269132568089, 0.00808778163675302)
(-31.766182020878944, 0.0208853433999961)
(17.930970740694246, 0.0055247725811907)
(-83.90477810390662, -0.00118069256826088)
(78.18720280258874, 0.00848556034437668)
(-27.920491874947288, 0.0237618456444247)
(100.17850107792617, -0.00662281179361756)
(-41.75863219681414, 0.00237233756116232)
(70.03304583393134, -0.00141455682093289)
(56.19578731101384, -0.0118062145075934)
(-33.63914876576596, -0.00294494505946919)
(-65.62070157914623, 0.0101105443428846)
(68.19679219405315, 0.00145264483782593)
(16.05658129884322, -0.0413161858948838)
(-19.767263832616866, -0.00501155653336639)
(-87.61205412539822, -0.00757273440507157)
(29.192176540757455, 0.00339355739212614)
(44.333027533124984, 0.0149652791502446)
(-97.74075893793497, -0.00678798975807558)
(27.920491874947288, 0.0237618456444247)
(26.050549805844287, -0.00380280664322429)
(-51.83479478770184, 0.0192917844000697)
(-4.057684310944882, 0.0244082523385398)
(-60.041304981472656, -0.0110500632779462)
(107.16558482583604, 0.00619101349298462)
(72.6078290944473, -0.00913760646746611)
(71.90395789936049, 0.00922705396366186)
(-93.89528015649516, -0.00706599004275581)
(-55.63039426031747, 0.00178078324424242)
(34.20402834693719, 0.0193968379825755)
(54.32504850754379, 0.00182357255545752)
(-95.81777312984083, 0.0104364334311013)
(46.205586058715355, -0.00214401813882137)
(-76.96802059935938, 0.0129923246024391)
(-53.758016025434124, -0.0123415828211396)
(-38.04964396418791, 0.0174365079794848)
(-9.771270215643433, -0.0678806979053923)
(-73.82638541658072, -0.0135451971227061)
(98.30741359303366, 0.00100771406838763)
(294.3915561803981, 0.000336510335259028)
(36.12618625168279, -0.0276799362050348)
(-60.608249556667886, 0.00163452492813244)
(2.2197585430683056, -0.0445918508116451)
(39.92237265903623, -0.00248145445914035)
(88.31592282351193, 0.00751238093422703)
(58.11814053320614, 0.0172061357112342)
(7.2001646388682765, -0.0137577302013311)
(-49.912482519663, -0.0132924267934124)
(-7.844177586961194, 0.127403457367743)
(-5.922222181775459, -0.111944270051768)
(65.62070157914623, 0.0101105443428846)
(48.04184334055685, 0.00206206968883238)
(-92.02422255674598, 0.00107651827944561)
(-11.647537375823008, 0.00850504207140542)
(-106.46171779459638, -0.00623194490968657)
(93.89528015649516, -0.00706599004275581)
(-39.92237265903623, -0.00248145445914035)
(-29.84255262109437, -0.0335077507454652)
(86.39290758899453, -0.0115749645985217)
(12.21006621224299, -0.054327818352075)
(-58.11814053320614, 0.0172061357112342)
(92.02422255674598, 0.00107651827944561)
(-85.7410306807642, 0.00115540657275765)
(76.31624083866579, -0.00129809506783185)
(-61.91359461335903, 0.00160006376663961)
(-16.05658129884322, -0.0413161858948838)
(22.340697641195526, -0.0296960177862559)
(80.1096524464143, -0.0124828154451489)
(32.33379665234729, -0.00306383491585732)
(4.057684310944882, 0.0244082523385398)
(-21.636751205414203, 0.0306620573156617)
(-48.04184334055685, 0.00206206968883238)
(-80.1096524464143, -0.0124828154451489)
(14.131724051907055, 0.0707491488647428)
(38.04964396418791, 0.0174365079794848)
(24.21427538302517, 0.00409118619885283)
(-91.45753619304172, -0.00725432846081434)
(43.063980383517524, 0.00230042798658153)
(10.34210547390096, 0.00957851236449886)
(60.041304981472656, -0.0110500632779462)
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:
$$x_{1} = 66.3245743061849$$
$$x_{2} = 5.92222218177546$$
$$x_{3} = 90.1879702595354$$
$$x_{4} = 83.9047781039066$$
$$x_{5} = -43.6291432937174$$
$$x_{6} = -36.1261862516828$$
$$x_{7} = -70.0330458339313$$
$$x_{8} = -63.749848917538$$
$$x_{9} = 49.912482519663$$
$$x_{10} = -26.0505498058443$$
$$x_{11} = -83.9047781039066$$
$$x_{12} = 100.178501077926$$
$$x_{13} = 70.0330458339313$$
$$x_{14} = 56.1957873110138$$
$$x_{15} = -33.639148765766$$
$$x_{16} = 16.0565812988432$$
$$x_{17} = -19.7672638326169$$
$$x_{18} = -87.6120541253982$$
$$x_{19} = -97.740758937935$$
$$x_{20} = 26.0505498058443$$
$$x_{21} = -60.0413049814727$$
$$x_{22} = 72.6078290944473$$
$$x_{23} = -93.8952801564952$$
$$x_{24} = 46.2055860587154$$
$$x_{25} = -53.7580160254341$$
$$x_{26} = -9.77127021564343$$
$$x_{27} = -73.8263854165807$$
$$x_{28} = 36.1261862516828$$
$$x_{29} = 2.21975854306831$$
$$x_{30} = 39.9223726590362$$
$$x_{31} = 7.20016463886828$$
$$x_{32} = -49.912482519663$$
$$x_{33} = -5.92222218177546$$
$$x_{34} = -106.461717794596$$
$$x_{35} = 93.8952801564952$$
$$x_{36} = -39.9223726590362$$
$$x_{37} = -29.8425526210944$$
$$x_{38} = 86.3929075889945$$
$$x_{39} = 12.210066212243$$
$$x_{40} = 76.3162408386658$$
$$x_{41} = -16.0565812988432$$
$$x_{42} = 22.3406976411955$$
$$x_{43} = 80.1096524464143$$
$$x_{44} = 32.3337966523473$$
$$x_{45} = -80.1096524464143$$
$$x_{46} = -91.4575361930417$$
$$x_{47} = 60.0413049814727$$
Puntos máximos de la función:
$$x_{47} = -17.9309707406942$$
$$x_{47} = 82.0326913256809$$
$$x_{47} = -71.9039578993605$$
$$x_{47} = -75.7494521674681$$
$$x_{47} = -114.667461020638$$
$$x_{47} = 61.913594613359$$
$$x_{47} = -14.1317240519071$$
$$x_{47} = -82.0326913256809$$
$$x_{47} = -31.7661820208789$$
$$x_{47} = 17.9309707406942$$
$$x_{47} = 78.1872028025887$$
$$x_{47} = -27.9204918749473$$
$$x_{47} = -41.7586321968141$$
$$x_{47} = -65.6207015791462$$
$$x_{47} = 68.1967921940531$$
$$x_{47} = 29.1921765407575$$
$$x_{47} = 44.333027533125$$
$$x_{47} = 27.9204918749473$$
$$x_{47} = -51.8347947877018$$
$$x_{47} = -4.05768431094488$$
$$x_{47} = 107.165584825836$$
$$x_{47} = 71.9039578993605$$
$$x_{47} = -55.6303942603175$$
$$x_{47} = 34.2040283469372$$
$$x_{47} = 54.3250485075438$$
$$x_{47} = -95.8177731298408$$
$$x_{47} = -76.9680205993594$$
$$x_{47} = -38.0496439641879$$
$$x_{47} = 98.3074135930337$$
$$x_{47} = 294.391556180398$$
$$x_{47} = -60.6082495566679$$
$$x_{47} = 88.3159228235119$$
$$x_{47} = 58.1181405332061$$
$$x_{47} = -7.84417758696119$$
$$x_{47} = 65.6207015791462$$
$$x_{47} = 48.0418433405569$$
$$x_{47} = -92.024222556746$$
$$x_{47} = -11.647537375823$$
$$x_{47} = -58.1181405332061$$
$$x_{47} = 92.024222556746$$
$$x_{47} = -85.7410306807642$$
$$x_{47} = -61.913594613359$$
$$x_{47} = 4.05768431094488$$
$$x_{47} = -21.6367512054142$$
$$x_{47} = -48.0418433405569$$
$$x_{47} = 14.1317240519071$$
$$x_{47} = 38.0496439641879$$
$$x_{47} = 24.2142753830252$$
$$x_{47} = 43.0639803835175$$
$$x_{47} = 10.342105473901$$
Decrece en los intervalos
$$\left[100.178501077926, \infty\right)$$
Crece en los intervalos
$$\left(-\infty, -106.461717794596\right]$$