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$$12 \sin^{3}{\left(3 x \right)} \cos{\left(3 x \right)} \operatorname{atan}^{3}{\left(2 x \right)} + \frac{6 \sin^{4}{\left(3 x \right)} \operatorname{atan}^{2}{\left(2 x \right)}}{4 x^{2} + 1} = 0$$
Resolvermos esta ecuaciónRaíces de esta ecuación
$$x_{1} = 58.1194719868896$$
$$x_{2} = 94.2477801894451$$
$$x_{3} = -27.7507699394451$$
$$x_{4} = -78.0162219399394$$
$$x_{5} = 6.28317681033055$$
$$x_{6} = 28.2743275849635$$
$$x_{7} = -93.7241838620119$$
$$x_{8} = 36.1283360152915$$
$$x_{9} = 43.9823032048267$$
$$x_{10} = -31.9395515690565$$
$$x_{11} = 16.2316646393078$$
$$x_{12} = 50.2654784216157$$
$$x_{13} = -49.7418944705192$$
$$x_{14} = -100.007368799869$$
$$x_{15} = -83.7757974571533$$
$$x_{16} = 100.007368799869$$
$$x_{17} = 14.137302547137$$
$$x_{18} = -41.8879092734202$$
$$x_{19} = -56.0250774875478$$
$$x_{20} = 38.2227289242278$$
$$x_{21} = -9.9486528927536$$
$$x_{22} = -65.9734545465241$$
$$x_{23} = -71.733037434713$$
$$x_{24} = -97.9129738127014$$
$$x_{25} = 80.1106168160882$$
$$x_{26} = 21.9911516357236$$
$$x_{27} = -5.76042622794097$$
$$x_{28} = -34.0339435255559$$
$$x_{29} = 48.1710808396552$$
$$x_{30} = -75.9218270828108$$
$$x_{31} = 60.2138665482131$$
$$x_{32} = -48.1710843027272$$
$$x_{33} = -51.8362887162079$$
$$x_{34} = 82.2050117093403$$
$$x_{35} = -7.85442793232242$$
$$x_{36} = 56.0250774875478$$
$$x_{37} = -95.818578833185$$
$$x_{38} = -61.7846467566113$$
$$x_{39} = -63.8790530122287$$
$$x_{40} = -53.9306830600289$$
$$x_{41} = 72.2566292967368$$
$$x_{42} = -73.8274322468957$$
$$x_{43} = 65.9734546541161$$
$$x_{44} = 34.0339435255559$$
$$x_{45} = -43.9823031830836$$
$$x_{46} = -29.845160301413$$
$$x_{47} = 12.0429593731892$$
$$x_{48} = -85.8701963703783$$
$$x_{49} = 78.0162219399394$$
$$x_{50} = -21.9911516343345$$
$$x_{51} = 0$$
Signos de extremos en los puntos:
(58.11947198688959, 3.81245334328431)
(94.2477801894451, 3.55947829879546e-23)
(-27.750769939445135, -3.74395320957084)
(-78.0162219399394, -3.82853836791674)
(6.283176810330551, 1.40051218448277e-18)
(28.274327584963466, 4.77227120488344e-19)
(-93.72418386201194, -3.83642962793549)
(36.12833601529148, 3.77424772911856)
(43.982303204826714, 4.12776170044334e-19)
(-31.939551569056547, -3.76106650102085)
(16.23166463930782, 3.65227808246266)
(50.26547842161573, 8.17138455670263e-20)
(-49.74189447051923, -3.80185605166276)
(-100.00736879986853, -3.83889426889535)
(-83.77579745715329, -6.02815288521775e-19)
(100.00736879986853, 3.83889426889535)
(14.137302547137025, 3.61994100445818)
(-41.88790927342023, -8.363571024944e-19)
(-56.02507748754777, -3.81009941798436)
(38.22272892422777, 3.77976426688823)
(-9.948652892753598, -3.51582839238658)
(-65.97345454652411, -1.87344926012261e-18)
(-71.733037434713, -3.82441852772562)
(-97.91297381270144, -3.83810775274243)
(80.11061681608822, 3.82976861597375)
(21.991151635723607, 2.63678727733102e-20)
(-5.760426227940968, -3.26952177038598)
(-34.033943525555884, -3.76805877434123)
(48.17108083965519, 5.54585202683598e-19)
(-75.9218270828108, -3.82724053268093)
(60.2138665482131, 3.81464439955514)
(-48.171084302727216, -2.67131557175863e-20)
(-51.83628871620793, -3.80482449180701)
(82.20501170934025, 3.83093642234329)
(-7.854427932322416, -3.42398322050265)
(56.02507748754777, 3.81009941798436)
(-95.81857883318504, -3.83728696887192)
(-61.784646756611345, -1.82356887284117e-18)
(-63.87905301222868, -1.00779601298045e-20)
(-53.93068306002891, -3.80756376370035)
(72.25662929673679, 2.81267607340039e-21)
(-73.82743224689571, -3.82586938347312)
(65.97345465411614, 1.96653751608659e-18)
(34.033943525555884, 3.76805877434123)
(-43.98230318308357, -4.06878595925984e-19)
(-29.845160301413035, -3.75310367891437)
(12.042959373189229, 3.57667599301974)
(-85.87019637037828, -1.98502365194774e-20)
(78.0162219399394, 3.82853836791674)
(-21.99115163433445, -2.63200335832004e-20)
(0, 0)
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:
$$x_{1} = -27.7507699394451$$
$$x_{2} = -78.0162219399394$$
$$x_{3} = -93.7241838620119$$
$$x_{4} = -31.9395515690565$$
$$x_{5} = -49.7418944705192$$
$$x_{6} = -100.007368799869$$
$$x_{7} = -56.0250774875478$$
$$x_{8} = -9.9486528927536$$
$$x_{9} = -71.733037434713$$
$$x_{10} = -97.9129738127014$$
$$x_{11} = -5.76042622794097$$
$$x_{12} = -34.0339435255559$$
$$x_{13} = -75.9218270828108$$
$$x_{14} = -51.8362887162079$$
$$x_{15} = -7.85442793232242$$
$$x_{16} = -95.818578833185$$
$$x_{17} = -53.9306830600289$$
$$x_{18} = -73.8274322468957$$
$$x_{19} = -29.845160301413$$
Puntos máximos de la función:
$$x_{19} = 58.1194719868896$$
$$x_{19} = 36.1283360152915$$
$$x_{19} = 16.2316646393078$$
$$x_{19} = 100.007368799869$$
$$x_{19} = 14.137302547137$$
$$x_{19} = 38.2227289242278$$
$$x_{19} = 80.1106168160882$$
$$x_{19} = 60.2138665482131$$
$$x_{19} = 82.2050117093403$$
$$x_{19} = 56.0250774875478$$
$$x_{19} = 34.0339435255559$$
$$x_{19} = 12.0429593731892$$
$$x_{19} = 78.0162219399394$$
Decrece en los intervalos
$$\left[-5.76042622794097, 12.0429593731892\right]$$
Crece en los intervalos
$$\left(-\infty, -100.007368799869\right]$$