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$$\frac{\cos{\left(x \right)}}{\sqrt{x + 12}} - \frac{\sin{\left(x \right)}}{2 \left(x + 12\right)^{\frac{3}{2}}} = 0$$
Resolvermos esta ecuaciónRaíces de esta ecuación
$$x_{1} = -83.2451874174528$$
$$x_{2} = -20.3606192102297$$
$$x_{3} = 80.1051841437789$$
$$x_{4} = 95.8139383484481$$
$$x_{5} = -246.612892139843$$
$$x_{6} = -61.2509049960415$$
$$x_{7} = -92.6707853296145$$
$$x_{8} = 20.4049237186924$$
$$x_{9} = -58.1086205572355$$
$$x_{10} = -17.1825802243184$$
$$x_{11} = -23.518563946472$$
$$x_{12} = 83.2469558567458$$
$$x_{13} = -64.3931064480803$$
$$x_{14} = 45.544404753626$$
$$x_{15} = 86.388716133896$$
$$x_{16} = 67.537955828092$$
$$x_{17} = 98.9556623140844$$
$$x_{18} = 2159.84471912395$$
$$x_{19} = 64.3961046557234$$
$$x_{20} = 10.9738138135803$$
$$x_{21} = -42.3950522612964$$
$$x_{22} = 17.2616740600802$$
$$x_{23} = -4.78154542352293$$
$$x_{24} = -32.9628756948497$$
$$x_{25} = -13.8768038497918$$
$$x_{26} = 89.530466036912$$
$$x_{27} = -26.6694663426443$$
$$x_{28} = -89.5289415121996$$
$$x_{29} = -39.2515626565503$$
$$x_{30} = -95.8126103158704$$
$$x_{31} = 51.8284454464525$$
$$x_{32} = 32.975606183108$$
$$x_{33} = 7.82877109194837$$
$$x_{34} = 130.372583226299$$
$$x_{35} = 58.1123327993243$$
$$x_{36} = 36.11792475218$$
$$x_{37} = -54.9662349182927$$
$$x_{38} = -76.9613232773934$$
$$x_{39} = 70.6797873522282$$
$$x_{40} = 48.6864472451997$$
$$x_{41} = -7.97765278370313$$
$$x_{42} = -98.9544185123724$$
$$x_{43} = 739.844404889277$$
$$x_{44} = -73.8193394518863$$
$$x_{45} = -45.5381862021436$$
$$x_{46} = -67.5352390029499$$
$$x_{47} = -86.3870764772726$$
$$x_{48} = 23.5478802931037$$
$$x_{49} = -48.6810559604372$$
$$x_{50} = -51.8237241138463$$
$$x_{51} = 54.970405592188$$
$$x_{52} = 29.8331785427431$$
$$x_{53} = 39.2601543142646$$
$$x_{54} = -174.355312618809$$
$$x_{55} = 4.68242629059323$$
$$x_{56} = 73.8216013862378$$
$$x_{57} = -1.6189236967475$$
$$x_{58} = -70.6773137311895$$
$$x_{59} = 26.6906152443659$$
$$x_{60} = -80.1032710071855$$
$$x_{61} = 92.6722064999962$$
$$x_{62} = -29.8170746041252$$
$$x_{63} = 61.2542313067072$$
$$x_{64} = 1.53386877017751$$
$$x_{65} = 42.4023102960826$$
$$x_{66} = 14.1180254124872$$
$$x_{67} = 76.9633997833194$$
$$x_{68} = -36.1075781231631$$
Signos de extremos en los puntos:
(-83.24518741745281, 0.118470859314563*I)
(-20.36061921022968, 0.345227614913729*I)
(80.10518414377891, -0.104196123854939)
(95.81393834844815, 0.0963070043817124)
(-246.61289213984344, 0.0652864534545343*I)
(-61.25090499604148, -0.142485448341385*I)
(-92.67078532961446, -0.111335462075447*I)
(20.404923718692416, 0.175647837207681)
(-58.10862055723546, 0.147259527305094*I)
(-17.18258022431841, -0.437235246704616*I)
(-23.51856394647204, -0.29436898605305*I)
(83.2469558567458, 0.102463329489896)
(-64.39310644808029, 0.13814753816133*I)
(45.54440475362601, 0.131820227093036)
(86.38871613389604, -0.10081420863209)
(67.53795582809201, -0.112125451909898)
(98.95566231408445, -0.0949337978787364)
(2159.8447191239497, -0.0214578202487205)
(64.39610465572345, 0.114407656900476)
(10.973813813580266, -0.208583821586473)
(-42.39505226129637, -0.181359287035697*I)
(17.261674060080185, -0.18483619686771)
(-4.781545423522932, 0.371311607475296)
(-32.96287569484965, 0.218348930912355*I)
(-13.876803849791798, 0.70534403100327*I)
(89.53046603691197, 0.0992422367551707)
(-26.66946634264428, 0.260940036537687*I)
(-89.52894151219957, 0.113568801119825*I)
(-39.25156265655028, 0.191527530038943*I)
(-95.81261031587036, 0.109228907168797*I)
(51.82844544645252, 0.125164031103941)
(32.975606183108034, 0.149102405997137)
(7.828771091948365, 0.224498825462677)
(130.37258322629853, -0.0838077419113687)
(58.11233279932431, 0.119424037054501)
(36.11792475218, -0.14415280923776)
(-54.96623491829275, -0.152548150435439*I)
(-76.96132327739336, 0.12406797807474*I)
(70.67978735222825, 0.109974598037377)
(48.68644724519966, -0.128362865458639)
(-7.977652783703126, -0.494800979651768)
(-98.95441851237238, -0.107237577018031*I)
(739.8444048892768, -0.036470012981631)
(-73.81933945188635, -0.127181404055952*I)
(-45.53818620214362, 0.172656111825905*I)
(-67.53523900294994, -0.134183178859072*I)
(-86.38707647727259, -0.115942175274977*I)
(23.547880293103667, -0.16770661356137)
(-48.681055960437156, -0.165096832866985*I)
(-51.823724113846254, 0.158450946253176*I)
(54.97040559218799, -0.122193029354218)
(29.8331785427431, -0.154599665307182)
(39.26015431426459, 0.13966557900936)
(-174.3553126188085, -0.0784810289540689*I)
(4.682426290593226, -0.244723354365609)
(73.82160138623779, -0.107942959874844)
(-1.6189236967474974, -0.310009960783476)
(-70.67731373118954, 0.130541657196597*I)
(26.690615244365915, 0.16075367884391)
(-80.10327100718554, -0.121172567414615*I)
(92.67220649999618, -0.0977415800959035)
(-29.81707460412521, -0.23681590008574*I)
(61.254231306707204, -0.116835151500422)
(1.5338687701775138, 0.271639448781314)
(42.40231029608263, -0.135572931404926)
(14.118025412487205, 0.195636670366637)
(76.96339978331943, 0.106019915869813)
(-36.1075781231631, -0.203624401120097*I)
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:
$$x_{1} = 80.1051841437789$$
$$x_{2} = 86.388716133896$$
$$x_{3} = 67.537955828092$$
$$x_{4} = 98.9556623140844$$
$$x_{5} = 2159.84471912395$$
$$x_{6} = 10.9738138135803$$
$$x_{7} = 17.2616740600802$$
$$x_{8} = 130.372583226299$$
$$x_{9} = 36.11792475218$$
$$x_{10} = 48.6864472451997$$
$$x_{11} = -7.97765278370313$$
$$x_{12} = 739.844404889277$$
$$x_{13} = 23.5478802931037$$
$$x_{14} = 54.970405592188$$
$$x_{15} = 29.8331785427431$$
$$x_{16} = 4.68242629059323$$
$$x_{17} = 73.8216013862378$$
$$x_{18} = -1.6189236967475$$
$$x_{19} = 92.6722064999962$$
$$x_{20} = 61.2542313067072$$
$$x_{21} = 42.4023102960826$$
Puntos máximos de la función:
$$x_{21} = 95.8139383484481$$
$$x_{21} = 20.4049237186924$$
$$x_{21} = 83.2469558567458$$
$$x_{21} = 45.544404753626$$
$$x_{21} = 64.3961046557234$$
$$x_{21} = -4.78154542352293$$
$$x_{21} = 89.530466036912$$
$$x_{21} = 51.8284454464525$$
$$x_{21} = 32.975606183108$$
$$x_{21} = 7.82877109194837$$
$$x_{21} = 58.1123327993243$$
$$x_{21} = 70.6797873522282$$
$$x_{21} = 39.2601543142646$$
$$x_{21} = 26.6906152443659$$
$$x_{21} = 1.53386877017751$$
$$x_{21} = 14.1180254124872$$
$$x_{21} = 76.9633997833194$$
Decrece en los intervalos
$$\left[2159.84471912395, \infty\right)$$
Crece en los intervalos
$$\left(-\infty, -7.97765278370313\right]$$