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$$\frac{5 x \cos{\left(5 x \right)}}{2} + \frac{\sin{\left(5 x \right)}}{2} = 0$$
Resolvermos esta ecuaciónRaíces de esta ecuación
$$x_{1} = 2.2171076812994$$
$$x_{2} = -19.7940544576791$$
$$x_{3} = -9.74304214351154$$
$$x_{4} = 58.1201523181367$$
$$x_{5} = 93.9340461723846$$
$$x_{6} = -75.7129112617625$$
$$x_{7} = 33.6162312807518$$
$$x_{8} = -58.1201523181367$$
$$x_{9} = 65.6598956580142$$
$$x_{10} = -5.97571730122148$$
$$x_{11} = 22.3071009434262$$
$$x_{12} = -63.7749580712467$$
$$x_{13} = -97.7039409261381$$
$$x_{14} = 29.2181806676368$$
$$x_{15} = 36.1294226358685$$
$$x_{16} = -11.6273326489798$$
$$x_{17} = 54.350288870431$$
$$x_{18} = 98.3322568409138$$
$$x_{19} = -81.9960560860671$$
$$x_{20} = -16.0246185629701$$
$$x_{21} = 73.1996552779432$$
$$x_{22} = -7.8590701962946$$
$$x_{23} = 5.97571730122148$$
$$x_{24} = 66.2882084144844$$
$$x_{25} = -48.0671997634234$$
$$x_{26} = 71.9430277612783$$
$$x_{27} = -49.9521239545497$$
$$x_{28} = 70.0580871282853$$
$$x_{29} = 17.9093115076498$$
$$x_{30} = -71.9430277612783$$
$$x_{31} = -76.9695396978816$$
$$x_{32} = -27.9616051255948$$
$$x_{33} = 24.1919168398108$$
$$x_{34} = -53.721978947155$$
$$x_{35} = -33.6162312807518$$
$$x_{36} = 49.9521239545497$$
$$x_{37} = -38.0143233336883$$
$$x_{38} = -29.8464703810162$$
$$x_{39} = -83.8810007159762$$
$$x_{40} = 0$$
$$x_{41} = 38.0143233336883$$
$$x_{42} = 78.2261684111119$$
$$x_{43} = 88.2792066729306$$
$$x_{44} = 61.8900215812096$$
$$x_{45} = 100.217204782048$$
$$x_{46} = -80.1111119720157$$
$$x_{47} = 4.09383348054819$$
$$x_{48} = -85.7659458277314$$
$$x_{49} = 34.2445279806789$$
$$x_{50} = 92.0490993001913$$
$$x_{51} = 26.0767529280317$$
$$x_{52} = -17.9093115076498$$
$$x_{53} = 10.3711121458304$$
$$x_{54} = -87.650891390247$$
$$x_{55} = 48.0671997634234$$
$$x_{56} = -21.6788343750783$$
$$x_{57} = 27.9616051255948$$
$$x_{58} = -40.5275322066585$$
$$x_{59} = -36.1294226358685$$
$$x_{60} = 76.3412254443279$$
$$x_{61} = 83.8810007159762$$
$$x_{62} = 60.0050862912537$$
$$x_{63} = -14.139995607722$$
$$x_{64} = -93.9340461723846$$
$$x_{65} = 39.8992292178262$$
$$x_{66} = 46.1822781354613$$
$$x_{67} = -31.7313463676968$$
$$x_{68} = -70.0580871282853$$
$$x_{69} = 32.3596404239143$$
$$x_{70} = -70.6864005839722$$
$$x_{71} = 10.9992105114993$$
$$x_{72} = 16.0246185629701$$
$$x_{73} = -51.8370504292459$$
$$x_{74} = -26.0767529280317$$
$$x_{75} = 56.2352197942696$$
$$x_{76} = -92.0490993001913$$
$$x_{77} = -73.8279691581203$$
$$x_{78} = 7.8590701962946$$
$$x_{79} = -43.6690538589529$$
$$x_{80} = -96.4473091988368$$
$$x_{81} = 44.2973593978424$$
$$x_{82} = -39.8992292178262$$
$$x_{83} = -102.73046914031$$
$$x_{84} = -41.7841395864668$$
$$x_{85} = 0.405751567622087$$
$$x_{86} = 14.139995607722$$
$$x_{87} = 81.9960560860671$$
$$x_{88} = -95.8189933876522$$
$$x_{89} = 12.2554749067139$$
$$x_{90} = 68.1731473224993$$
$$x_{91} = -60.0050862912537$$
$$x_{92} = 90.1641527925887$$
$$x_{93} = 80.1111119720157$$
$$x_{94} = -65.6598956580142$$
$$x_{95} = -61.8900215812096$$
$$x_{96} = -4.09383348054819$$
Signos de extremos en los puntos:
(2.2171076812994044, -1.104070801593)
(-19.79405445767914, -9.89652206531187)
(-9.743042143511545, -4.87049502253679)
(58.12015231813666, 29.0599041032359)
(93.93404617238458, -46.9669166288809)
(-75.71291126176251, 37.8563235537031)
(33.61623128075184, -16.8078181729278)
(-58.12015231813666, 29.0599041032359)
(65.65989565801415, 32.829795530099)
(-5.975717301221478, -2.98618661591868)
(22.307100943426203, -11.153102210992)
(-63.774958071246694, -31.8873222354224)
(-97.70394092613815, -48.8518681133739)
(29.21818066763675, 14.6087480931869)
(36.129422635868536, -18.0644345415717)
(-11.627332648979833, 5.81280647280857)
(54.350288870431015, 27.1749604454217)
(98.33225684091383, 49.1660267247439)
(-81.99605608606707, 40.9979060864925)
(-16.02461856297005, -8.01168531456592)
(73.19965527794324, 36.5996910270713)
(-7.8590701962945975, 3.92826330068918)
(5.975717301221478, -2.98618661591868)
(66.28820841448444, -33.1439533518795)
(-48.06719976342337, 24.0333918423375)
(71.94302776127826, 35.9713748825687)
(-49.95212395454971, -24.975861787994)
(70.0580871282853, -35.0289008263191)
(17.90931150764984, 8.95409743728852)
(-71.94302776127826, 35.9713748825687)
(-76.96953969788157, 38.4846399280734)
(-27.961605125594843, 13.9804449432592)
(24.19191683981079, 12.0955450798839)
(-53.72197894715498, -26.8608033319601)
(-33.61623128075184, -16.8078181729278)
(49.95212395454971, -24.975861787994)
(-38.01432333368825, 19.006898613565)
(-29.846470381016186, -14.9229001537981)
(-83.88100071597616, -41.9403811419883)
(0, 0)
(38.01432333368825, 19.006898613565)
(78.22616841111187, 39.1129563717226)
(88.27920667293058, 44.1394900599432)
(61.89002158120955, 30.9448492149352)
(100.21720478204843, -50.1085026080563)
(-80.11111197201575, -40.055431159963)
(4.09383348054819, 2.04447840582523)
(-85.76594582773144, 42.8828563179474)
(34.24452798067887, 17.121971980352)
(92.04909930019132, 46.0244410128068)
(26.076752928031663, -13.0379929976053)
(-17.90931150764984, 8.95409743728852)
(10.371112145830393, 5.18459212502015)
(-87.65089139024695, -43.825331606598)
(48.06719976342337, 24.0333918423375)
(-21.67883437507826, 10.8389559375689)
(27.961605125594843, 13.9804449432592)
(-40.52753220665854, 20.2635193619954)
(-36.129422635868536, -18.0644345415717)
(76.34122544432788, -38.1704817320146)
(83.88100071597616, -41.9403811419883)
(60.00508629125367, -30.0023764944761)
(-14.139995607722, 7.06929069615931)
(-93.93404617238458, -46.9669166288809)
(39.89922921782617, -19.949363982228)
(46.18227813546127, -23.0909225374999)
(-31.731346367696773, 15.8653580474548)
(-70.0580871282853, -35.0289008263191)
(32.3596404239143, -16.1795111938907)
(-70.68640058397224, 35.3430588229075)
(10.999210511499278, -5.49869632496976)
(16.02461856297005, -8.01168531456592)
(-51.83705042924591, 25.9183323045659)
(-26.076752928031663, -13.0379929976053)
(56.23521979426956, -28.1174320743189)
(-92.04909930019132, 46.0244410128068)
(-73.82796915812025, -36.9138491297843)
(7.8590701962945975, 3.92826330068918)
(-43.66905385895287, -21.8342979379641)
(-96.44730919883683, -48.2235509161966)
(44.297359397842364, 22.148453955282)
(-39.89922921782617, -19.949363982228)
(-102.73046914030988, -51.3651372283278)
(-41.78413958646682, 20.8918304720873)
(0.40575156762208686, 0.181970574115965)
(14.139995607722, 7.06929069615931)
(81.99605608606707, 40.9979060864925)
(-95.81899338765217, 47.9093923307247)
(12.255474906713932, -6.12692165444766)
(68.17314732249932, 34.0864269768755)
(-60.00508629125367, -30.0023764944761)
(90.16415279258867, -45.0819654878813)
(80.11111197201575, -40.055431159963)
(-65.65989565801415, 32.829795530099)
(-61.89002158120955, 30.9448492149352)
(-4.09383348054819, 2.04447840582523)
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:
$$x_{1} = 2.2171076812994$$
$$x_{2} = -19.7940544576791$$
$$x_{3} = -9.74304214351154$$
$$x_{4} = 93.9340461723846$$
$$x_{5} = 33.6162312807518$$
$$x_{6} = -5.97571730122148$$
$$x_{7} = 22.3071009434262$$
$$x_{8} = -63.7749580712467$$
$$x_{9} = -97.7039409261381$$
$$x_{10} = 36.1294226358685$$
$$x_{11} = -16.0246185629701$$
$$x_{12} = 5.97571730122148$$
$$x_{13} = 66.2882084144844$$
$$x_{14} = -49.9521239545497$$
$$x_{15} = 70.0580871282853$$
$$x_{16} = -53.721978947155$$
$$x_{17} = -33.6162312807518$$
$$x_{18} = 49.9521239545497$$
$$x_{19} = -29.8464703810162$$
$$x_{20} = -83.8810007159762$$
$$x_{21} = 0$$
$$x_{22} = 100.217204782048$$
$$x_{23} = -80.1111119720157$$
$$x_{24} = 26.0767529280317$$
$$x_{25} = -87.650891390247$$
$$x_{26} = -36.1294226358685$$
$$x_{27} = 76.3412254443279$$
$$x_{28} = 83.8810007159762$$
$$x_{29} = 60.0050862912537$$
$$x_{30} = -93.9340461723846$$
$$x_{31} = 39.8992292178262$$
$$x_{32} = 46.1822781354613$$
$$x_{33} = -70.0580871282853$$
$$x_{34} = 32.3596404239143$$
$$x_{35} = 10.9992105114993$$
$$x_{36} = 16.0246185629701$$
$$x_{37} = -26.0767529280317$$
$$x_{38} = 56.2352197942696$$
$$x_{39} = -73.8279691581203$$
$$x_{40} = -43.6690538589529$$
$$x_{41} = -96.4473091988368$$
$$x_{42} = -39.8992292178262$$
$$x_{43} = -102.73046914031$$
$$x_{44} = 12.2554749067139$$
$$x_{45} = -60.0050862912537$$
$$x_{46} = 90.1641527925887$$
$$x_{47} = 80.1111119720157$$
Puntos máximos de la función:
$$x_{47} = 58.1201523181367$$
$$x_{47} = -75.7129112617625$$
$$x_{47} = -58.1201523181367$$
$$x_{47} = 65.6598956580142$$
$$x_{47} = 29.2181806676368$$
$$x_{47} = -11.6273326489798$$
$$x_{47} = 54.350288870431$$
$$x_{47} = 98.3322568409138$$
$$x_{47} = -81.9960560860671$$
$$x_{47} = 73.1996552779432$$
$$x_{47} = -7.8590701962946$$
$$x_{47} = -48.0671997634234$$
$$x_{47} = 71.9430277612783$$
$$x_{47} = 17.9093115076498$$
$$x_{47} = -71.9430277612783$$
$$x_{47} = -76.9695396978816$$
$$x_{47} = -27.9616051255948$$
$$x_{47} = 24.1919168398108$$
$$x_{47} = -38.0143233336883$$
$$x_{47} = 38.0143233336883$$
$$x_{47} = 78.2261684111119$$
$$x_{47} = 88.2792066729306$$
$$x_{47} = 61.8900215812096$$
$$x_{47} = 4.09383348054819$$
$$x_{47} = -85.7659458277314$$
$$x_{47} = 34.2445279806789$$
$$x_{47} = 92.0490993001913$$
$$x_{47} = -17.9093115076498$$
$$x_{47} = 10.3711121458304$$
$$x_{47} = 48.0671997634234$$
$$x_{47} = -21.6788343750783$$
$$x_{47} = 27.9616051255948$$
$$x_{47} = -40.5275322066585$$
$$x_{47} = -14.139995607722$$
$$x_{47} = -31.7313463676968$$
$$x_{47} = -70.6864005839722$$
$$x_{47} = -51.8370504292459$$
$$x_{47} = -92.0490993001913$$
$$x_{47} = 7.8590701962946$$
$$x_{47} = 44.2973593978424$$
$$x_{47} = -41.7841395864668$$
$$x_{47} = 0.405751567622087$$
$$x_{47} = 14.139995607722$$
$$x_{47} = 81.9960560860671$$
$$x_{47} = -95.8189933876522$$
$$x_{47} = 68.1731473224993$$
$$x_{47} = -65.6598956580142$$
$$x_{47} = -61.8900215812096$$
$$x_{47} = -4.09383348054819$$
Decrece en los intervalos
$$\left[100.217204782048, \infty\right)$$
Crece en los intervalos
$$\left(-\infty, -102.73046914031\right]$$