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$$- \frac{1}{2 x^{3}} x \sin{\left(x \right)} - \frac{3 \left(x \cos{\left(x \right)} - \sin{\left(x \right)}\right)}{2 x^{4}} = 0$$
Resolvermos esta ecuaciónRaíces de esta ecuación
$$x_{1} = -47.0601416127605$$
$$x_{2} = 84.7876191237855$$
$$x_{3} = -28.1678297079936$$
$$x_{4} = -53.3508435852932$$
$$x_{5} = -15.5146030108867$$
$$x_{6} = 94.2159378620236$$
$$x_{7} = 28.1678297079936$$
$$x_{8} = 59.6399585795582$$
$$x_{9} = 47.0601416127605$$
$$x_{10} = -50.205728336738$$
$$x_{11} = 62.7840702561801$$
$$x_{12} = -188.47964237706$$
$$x_{13} = -12.3229409705666$$
$$x_{14} = -69.0716051946096$$
$$x_{15} = -87.9304764379571$$
$$x_{16} = 81.6446644013823$$
$$x_{17} = 97.3585583298596$$
$$x_{18} = -100.501114500159$$
$$x_{19} = -84.7876191237855$$
$$x_{20} = -59.6399585795582$$
$$x_{21} = 78.5016005602391$$
$$x_{22} = 34.470488331285$$
$$x_{23} = -78.5016005602391$$
$$x_{24} = -5.76345919689455$$
$$x_{25} = -75.3584139333214$$
$$x_{26} = -43.9139818113646$$
$$x_{27} = 15.5146030108867$$
$$x_{28} = 9.09501133047636$$
$$x_{29} = -91.0732464360163$$
$$x_{30} = 69.0716051946096$$
$$x_{31} = 21.8538742227098$$
$$x_{32} = -37.6193657535884$$
$$x_{33} = -72.2150884704073$$
$$x_{34} = 5.76345919689455$$
$$x_{35} = 50.205728336738$$
$$x_{36} = 75.3584139333214$$
$$x_{37} = -97.3585583298596$$
$$x_{38} = 31.3201417074472$$
$$x_{39} = 25.0128032022896$$
$$x_{40} = -40.7671158214068$$
$$x_{41} = 18.6890363553628$$
$$x_{42} = 100.501114500159$$
$$x_{43} = -34.470488331285$$
$$x_{44} = -21.8538742227098$$
$$x_{45} = -31.3201417074472$$
$$x_{46} = -56.495566261812$$
$$x_{47} = -65.9279415029586$$
$$x_{48} = -9.09501133047636$$
$$x_{49} = -81.6446644013823$$
$$x_{50} = -62.7840702561801$$
$$x_{51} = 56.495566261812$$
$$x_{52} = 116.213113540404$$
$$x_{53} = 40.7671158214068$$
$$x_{54} = -94.2159378620236$$
$$x_{55} = 43.9139818113646$$
$$x_{56} = 53.3508435852932$$
$$x_{57} = 65.9279415029586$$
$$x_{58} = 87.9304764379571$$
$$x_{59} = 91.0732464360163$$
$$x_{60} = -18.6890363553628$$
$$x_{61} = 72.2150884704073$$
$$x_{62} = 37.6193657535884$$
$$x_{63} = 12.3229409705666$$
$$x_{64} = -25.0128032022896$$
Signos de extremos en los puntos:
(-47.06014161276053, -0.000225615636669507)
(84.78761912378548, -6.95367658389369e-5)
(-28.167829707993622, -0.000628985506814357)
(-53.35084358529321, -0.000175573282983773)
(-15.514603010886749, -0.00206426604519197)
(94.21593786202358, 5.63180815586409e-5)
(28.167829707993622, -0.000628985506814357)
(59.639958579558154, -0.000140511578744414)
(47.06014161276053, -0.000225615636669507)
(-50.205728336738034, 0.00019824619552509)
(62.78407025618014, 0.000126796055545467)
(-188.4796423770602, 1.40741691940626e-5)
(-12.322940970566583, 0.00325994373348013)
(-69.0716051946096, 0.000104769366606048)
(-87.93047643795707, 6.46557092537797e-5)
(81.64466440138234, 7.49922938134965e-5)
(97.35855832985965, -5.27415632271757e-5)
(-100.50111450015908, 4.9495275149513e-5)
(-84.78761912378548, -6.95367658389369e-5)
(-59.639958579558154, -0.000140511578744414)
(78.50160056023911, -8.11161341505881e-5)
(34.47048833128499, -0.000420267871095791)
(-78.50160056023911, -8.11161341505881e-5)
(-5.76345919689455, 0.0143618156936512)
(-75.3584139333214, 8.8022107503451e-5)
(-43.91398181136465, 0.000259075472442818)
(15.514603010886749, -0.00206426604519197)
(9.095011330476355, -0.00593406337793414)
(-91.07324643601635, -6.02711965903649e-5)
(69.0716051946096, 0.000104769366606048)
(21.853874222709766, -0.00104362593723816)
(-37.619365753588426, 0.000352928123452401)
(-72.21508847040727, -9.58493466083015e-5)
(5.76345919689455, 0.0143618156936512)
(50.205728336738034, 0.00019824619552509)
(75.3584139333214, 8.8022107503451e-5)
(-97.35855832985965, -5.27415632271757e-5)
(31.320141707447174, 0.000508929311415012)
(25.01280320228961, 0.000797262893691229)
(-40.767115821406804, -0.000300578355805196)
(18.689036355362823, 0.00142535541473414)
(100.50111450015908, 4.9495275149513e-5)
(-34.47048833128499, -0.000420267871095791)
(-21.853874222709766, -0.00104362593723816)
(-31.320141707447174, 0.000508929311415012)
(-56.49556626181198, 0.00015658028339586)
(-65.92794150295865, -0.000114995552337877)
(-9.095011330476355, -0.00593406337793414)
(-81.64466440138234, 7.49922938134965e-5)
(-62.78407025618014, 0.000126796055545467)
(56.49556626181198, 0.00015658028339586)
(116.21311354040374, -3.70178754642193e-5)
(40.767115821406804, -0.000300578355805196)
(-94.21593786202358, 5.63180815586409e-5)
(43.91398181136465, 0.000259075472442818)
(53.35084358529321, -0.000175573282983773)
(65.92794150295865, -0.000114995552337877)
(87.93047643795707, 6.46557092537797e-5)
(91.07324643601635, -6.02711965903649e-5)
(-18.689036355362823, 0.00142535541473414)
(72.21508847040727, -9.58493466083015e-5)
(37.619365753588426, 0.000352928123452401)
(12.322940970566583, 0.00325994373348013)
(-25.01280320228961, 0.000797262893691229)
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:
$$x_{1} = -47.0601416127605$$
$$x_{2} = 84.7876191237855$$
$$x_{3} = -28.1678297079936$$
$$x_{4} = -53.3508435852932$$
$$x_{5} = -15.5146030108867$$
$$x_{6} = 28.1678297079936$$
$$x_{7} = 59.6399585795582$$
$$x_{8} = 47.0601416127605$$
$$x_{9} = 97.3585583298596$$
$$x_{10} = -84.7876191237855$$
$$x_{11} = -59.6399585795582$$
$$x_{12} = 78.5016005602391$$
$$x_{13} = 34.470488331285$$
$$x_{14} = -78.5016005602391$$
$$x_{15} = 15.5146030108867$$
$$x_{16} = 9.09501133047636$$
$$x_{17} = -91.0732464360163$$
$$x_{18} = 21.8538742227098$$
$$x_{19} = -72.2150884704073$$
$$x_{20} = -97.3585583298596$$
$$x_{21} = -40.7671158214068$$
$$x_{22} = -34.470488331285$$
$$x_{23} = -21.8538742227098$$
$$x_{24} = -65.9279415029586$$
$$x_{25} = -9.09501133047636$$
$$x_{26} = 116.213113540404$$
$$x_{27} = 40.7671158214068$$
$$x_{28} = 53.3508435852932$$
$$x_{29} = 65.9279415029586$$
$$x_{30} = 91.0732464360163$$
$$x_{31} = 72.2150884704073$$
Puntos máximos de la función:
$$x_{31} = 94.2159378620236$$
$$x_{31} = -50.205728336738$$
$$x_{31} = 62.7840702561801$$
$$x_{31} = -188.47964237706$$
$$x_{31} = -12.3229409705666$$
$$x_{31} = -69.0716051946096$$
$$x_{31} = -87.9304764379571$$
$$x_{31} = 81.6446644013823$$
$$x_{31} = -100.501114500159$$
$$x_{31} = -5.76345919689455$$
$$x_{31} = -75.3584139333214$$
$$x_{31} = -43.9139818113646$$
$$x_{31} = 69.0716051946096$$
$$x_{31} = -37.6193657535884$$
$$x_{31} = 5.76345919689455$$
$$x_{31} = 50.205728336738$$
$$x_{31} = 75.3584139333214$$
$$x_{31} = 31.3201417074472$$
$$x_{31} = 25.0128032022896$$
$$x_{31} = 18.6890363553628$$
$$x_{31} = 100.501114500159$$
$$x_{31} = -31.3201417074472$$
$$x_{31} = -56.495566261812$$
$$x_{31} = -81.6446644013823$$
$$x_{31} = -62.7840702561801$$
$$x_{31} = 56.495566261812$$
$$x_{31} = -94.2159378620236$$
$$x_{31} = 43.9139818113646$$
$$x_{31} = 87.9304764379571$$
$$x_{31} = -18.6890363553628$$
$$x_{31} = 37.6193657535884$$
$$x_{31} = 12.3229409705666$$
$$x_{31} = -25.0128032022896$$
Decrece en los intervalos
$$\left[116.213113540404, \infty\right)$$
Crece en los intervalos
$$\left(-\infty, -97.3585583298596\right]$$