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$$- 2 x^{2} \cos{\left(3 x \right)} - 2 x \left(- 3 x^{2} \sin{\left(3 x \right)} + 2 x \cos{\left(3 x \right)} + 3 \left(1 - x\right) \cos{\left(3 x \right)} - \sin{\left(3 x \right)}\right) - 2 \left(1 - x\right) \sin{\left(3 x \right)} = 0$$
Resolvermos esta ecuaciónRaíces de esta ecuación
$$x_{1} = -87.9645512254701$$
$$x_{2} = 65.9735222979839$$
$$x_{3} = -13.6117757944157$$
$$x_{4} = 74.3510864259024$$
$$x_{5} = -68.0677688940187$$
$$x_{6} = 21.9918368635693$$
$$x_{7} = -79.5869612711768$$
$$x_{8} = -72.2565671961847$$
$$x_{9} = 39.7937173568211$$
$$x_{10} = 28.2747504881455$$
$$x_{11} = 59.6903539565878$$
$$x_{12} = -48.170943745812$$
$$x_{13} = 52.359999115404$$
$$x_{14} = 96.3422106200121$$
$$x_{15} = 72.256694868833$$
$$x_{16} = 8.38228224782493$$
$$x_{17} = -90.0589483078959$$
$$x_{18} = -33.5100249724637$$
$$x_{19} = 78.5398703718322$$
$$x_{20} = 17.8034078744262$$
$$x_{21} = 56.5487719825944$$
$$x_{22} = -4.17043227881737$$
$$x_{23} = 100.530997894843$$
$$x_{24} = 11.5216720168374$$
$$x_{25} = 0$$
$$x_{26} = 48.1712309634192$$
$$x_{27} = -35.6044539327594$$
$$x_{28} = -39.7932965318971$$
$$x_{29} = -2.02786118086652$$
$$x_{30} = -11.5166730356884$$
$$x_{31} = -55.5013620260354$$
$$x_{32} = -52.3597560036917$$
$$x_{33} = -41.8877121419601$$
$$x_{34} = 92.1534237536942$$
$$x_{35} = -85.8701539964212$$
$$x_{36} = 32.4634401831824$$
$$x_{37} = 43.9824694051414$$
$$x_{38} = -21.9904602437192$$
$$x_{39} = 15.7093104545096$$
$$x_{40} = -59.6901668795313$$
$$x_{41} = -19.8959128503852$$
$$x_{42} = 90.0590304978814$$
$$x_{43} = -43.9821248940245$$
$$x_{44} = -46.0765352954475$$
$$x_{45} = 68.0679127613871$$
$$x_{46} = -83.7757566059074$$
$$x_{47} = 19.8975940242995$$
$$x_{48} = -30.3683678105346$$
$$x_{49} = 87.9646373755162$$
$$x_{50} = -77.4925632863524$$
$$x_{51} = 54.4543850492753$$
$$x_{52} = 61.7847428259826$$
$$x_{53} = -92.1533452568736$$
$$x_{54} = -26.1794529021746$$
$$x_{55} = 37.6993462713932$$
$$x_{56} = -61.7845682149693$$
$$x_{57} = -28.273917264214$$
$$x_{58} = 26.1804246396561$$
$$x_{59} = -24.0849697237312$$
$$x_{60} = -95.2949404554302$$
$$x_{61} = 76.4454782703127$$
$$x_{62} = 4.20700066076947$$
$$x_{63} = -57.5957648520122$$
$$x_{64} = -62.8317686516205$$
$$x_{65} = 6.29147622227546$$
$$x_{66} = 41.8880919520471$$
$$x_{67} = 63.8791322982152$$
$$x_{68} = -17.8013087430214$$
$$x_{69} = 24.0861176040221$$
$$x_{70} = 2.15808850992003$$
$$x_{71} = 30.3690901502898$$
$$x_{72} = 70.1623036339133$$
$$x_{73} = 46.0768492087845$$
$$x_{74} = -15.7066158515165$$
$$x_{75} = 10.4749958368593$$
$$x_{76} = 16.7563452754841$$
$$x_{77} = 85.8702443997733$$
$$x_{78} = -63.8789689475609$$
$$x_{79} = 50.2656143509073$$
$$x_{80} = 58.6431597752133$$
$$x_{81} = -81.6813590371603$$
$$x_{82} = -9.42105198379253$$
$$x_{83} = 20.9447097509249$$
$$x_{84} = -50.2653505632743$$
$$x_{85} = 83.7758515854944$$
$$x_{86} = -70.1621682263002$$
$$x_{87} = -99.4837336857622$$
$$x_{88} = -94.2477420841309$$
$$x_{89} = 98.4366042106844$$
$$x_{90} = -65.9733691526097$$
$$x_{91} = -37.698877411849$$
$$x_{92} = 94.2478171312268$$
$$x_{93} = -76.4453642043055$$
$$x_{94} = -7.32425123309633$$
Signos de extremos en los puntos:
(-87.96455122547006, 1361299.58273911 + E)
(65.97352229798388, 574298.271827806 + E)
(-13.611775794415664, -5046.05762682675 + E)
(74.35108642590244, 822036.124034965 + E)
(-68.06776889401866, -630748.069009655 + E)
(21.99183686356929, 21270.3512128818 + E)
(-79.58696127117683, 1008223.07271253 + E)
(-72.25656719618469, -754506.750576209 + E)
(39.79371735682107, -126027.907637773 + E)
(28.27475048814548, 45207.1867381598 + E)
(59.69035395658781, 425344.12025037 + E)
(-48.170943745812004, 223557.572379574 + E)
(52.359999115403966, -287095.17354117 + E)
(96.34221062001207, -1788460.4233885 + E)
(72.25669486883304, 754506.750576209 + E)
(8.38228224782493, -1176.05999058124 + E)
(-90.05894830789588, 1460868.77555957 + E)
(-33.510024972463725, 75260.3019912521 + E)
(78.53987037183224, 968946.158990389 + E)
(17.803407874426203, 11284.0440046831 + E)
(56.548771982594374, -361657.228879213 + E)
(-4.170432278817372, 147.222486590438 + E)
(100.5309978948431, -2032027.35846666 + E)
(11.521672016837417, 3057.07558127174 + E)
(0, E)
(48.17123096341922, -223557.572379574 + E)
(-35.60445393275944, 90271.9316745479 + E)
(-39.79329653189708, 126027.907637773 + E)
(-2.0278611808665152, 18.7817935340658 + E)
(-11.51667303568837, -3057.07558102077 + E)
(-55.501362026035395, -341934.940482753 + E)
(-52.359756003691686, 287095.17354117 + E)
(-41.88771214196009, 146992.742941149 + E)
(92.15342375369418, -1565178.48358227 + E)
(-85.87015399642118, 1266360.66058247 + E)
(32.46344018318242, 68422.8447537987 + E)
(43.98246940514135, -170162.469150071 + E)
(-21.99046024371924, -21270.3512128766 + E)
(15.70931045450963, 7751.63266026757 + E)
(-59.690166879531276, -425344.12025037 + E)
(-19.89591285038517, -15753.535489704 + E)
(90.05903049788144, -1460868.77555957 + E)
(-43.982124894024516, 170162.469150071 + E)
(-46.07653529544746, 195647.330787589 + E)
(68.06791276138706, 630748.069009655 + E)
(-83.77575660590739, 1175941.7645513 + E)
(19.89759402429951, 15753.5354897135 + E)
(-30.368367810534615, -56015.7426793193 + E)
(87.96463737551619, -1361299.58273911 + E)
(-77.49256328635238, 930702.787828786 + E)
(54.45438504927531, -322943.022172022 + E)
(61.784742825982576, 471706.541984148 + E)
(-92.15334525687359, 1565178.48358227 + E)
(-26.17945290217456, -35886.93246595 + E)
(37.699346271393175, -107157.7187205 + E)
(-61.784568214969305, -471706.541984148 + E)
(-28.273917264214028, -45207.1867381586 + E)
(26.180424639656117, 35886.9324659519 + E)
(-24.084969723731177, -27944.7354242647 + E)
(-95.29494045543022, -1730772.67154853 + E)
(76.44547827031268, 893479.178660491 + E)
(4.20700066076947, -147.222587641142 + E)
(-57.5957648520122, -382123.667928119 + E)
(-62.83176865162048, 496100.442797604 + E)
(6.291476222275462, -496.256919058581 + E)
(41.88809195204712, -146992.742941149 + E)
(63.87913229821518, 521321.177664704 + E)
(-17.801308743021362, -11284.0440046646 + E)
(24.086117604022085, 27944.7354242677 + E)
(2.1580885099200318, -18.7867519326205 + E)
(30.369090150289818, 56015.7426793201 + E)
(70.16230363391333, 690780.813746827 + E)
(46.076849208784495, -195647.330787589 + E)
(-15.706615851516478, -7751.63266022834 + E)
(10.474995836859318, -2296.85614979228 + E)
(16.756345275484108, -9407.59356246078 + E)
(85.87024439977327, -1266360.66058247 + E)
(-63.87896894756095, -521321.177664704 + E)
(50.265614350907306, -254003.438454135 + E)
(58.64315977521328, -403348.038196235 + E)
(-81.68135903716026, 1089932.65010736 + E)
(-9.421051983792534, -1674.44424991783 + E)
(20.94470975092492, -18374.1375585909 + E)
(-50.26535056327428, 254003.438454135 + E)
(83.77585158549442, -1175941.7645513 + E)
(-70.16216822630015, -690780.813746826 + E)
(-99.4837336857622, -1969185.6744047 + E)
(-94.24774208413095, 1674338.95134572 + E)
(98.43660421068435, -1907653.14424925 + E)
(-65.97336915260975, -574298.271827805 + E)
(-37.69887741184902, 107157.7187205 + E)
(94.24781713122677, -1674338.95134572 + E)
(-76.44536420430552, -893479.178660491 + E)
(-7.32425123309633, -787.923837275761 + E)
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:
$$x_{1} = -13.6117757944157$$
$$x_{2} = -68.0677688940187$$
$$x_{3} = -72.2565671961847$$
$$x_{4} = 39.7937173568211$$
$$x_{5} = 52.359999115404$$
$$x_{6} = 96.3422106200121$$
$$x_{7} = 8.38228224782493$$
$$x_{8} = 56.5487719825944$$
$$x_{9} = 100.530997894843$$
$$x_{10} = 48.1712309634192$$
$$x_{11} = -11.5166730356884$$
$$x_{12} = -55.5013620260354$$
$$x_{13} = 92.1534237536942$$
$$x_{14} = 43.9824694051414$$
$$x_{15} = -21.9904602437192$$
$$x_{16} = -59.6901668795313$$
$$x_{17} = -19.8959128503852$$
$$x_{18} = 90.0590304978814$$
$$x_{19} = -30.3683678105346$$
$$x_{20} = 87.9646373755162$$
$$x_{21} = 54.4543850492753$$
$$x_{22} = -26.1794529021746$$
$$x_{23} = 37.6993462713932$$
$$x_{24} = -61.7845682149693$$
$$x_{25} = -28.273917264214$$
$$x_{26} = -24.0849697237312$$
$$x_{27} = -95.2949404554302$$
$$x_{28} = 4.20700066076947$$
$$x_{29} = -57.5957648520122$$
$$x_{30} = 6.29147622227546$$
$$x_{31} = 41.8880919520471$$
$$x_{32} = -17.8013087430214$$
$$x_{33} = 2.15808850992003$$
$$x_{34} = 46.0768492087845$$
$$x_{35} = -15.7066158515165$$
$$x_{36} = 10.4749958368593$$
$$x_{37} = 16.7563452754841$$
$$x_{38} = 85.8702443997733$$
$$x_{39} = -63.8789689475609$$
$$x_{40} = 50.2656143509073$$
$$x_{41} = 58.6431597752133$$
$$x_{42} = -9.42105198379253$$
$$x_{43} = 20.9447097509249$$
$$x_{44} = 83.7758515854944$$
$$x_{45} = -70.1621682263002$$
$$x_{46} = -99.4837336857622$$
$$x_{47} = 98.4366042106844$$
$$x_{48} = -65.9733691526097$$
$$x_{49} = 94.2478171312268$$
$$x_{50} = -76.4453642043055$$
$$x_{51} = -7.32425123309633$$
Puntos máximos de la función:
$$x_{51} = -87.9645512254701$$
$$x_{51} = 65.9735222979839$$
$$x_{51} = 74.3510864259024$$
$$x_{51} = 21.9918368635693$$
$$x_{51} = -79.5869612711768$$
$$x_{51} = 28.2747504881455$$
$$x_{51} = 59.6903539565878$$
$$x_{51} = -48.170943745812$$
$$x_{51} = 72.256694868833$$
$$x_{51} = -90.0589483078959$$
$$x_{51} = -33.5100249724637$$
$$x_{51} = 78.5398703718322$$
$$x_{51} = 17.8034078744262$$
$$x_{51} = -4.17043227881737$$
$$x_{51} = 11.5216720168374$$
$$x_{51} = 0$$
$$x_{51} = -35.6044539327594$$
$$x_{51} = -39.7932965318971$$
$$x_{51} = -2.02786118086652$$
$$x_{51} = -52.3597560036917$$
$$x_{51} = -41.8877121419601$$
$$x_{51} = -85.8701539964212$$
$$x_{51} = 32.4634401831824$$
$$x_{51} = 15.7093104545096$$
$$x_{51} = -43.9821248940245$$
$$x_{51} = -46.0765352954475$$
$$x_{51} = 68.0679127613871$$
$$x_{51} = -83.7757566059074$$
$$x_{51} = 19.8975940242995$$
$$x_{51} = -77.4925632863524$$
$$x_{51} = 61.7847428259826$$
$$x_{51} = -92.1533452568736$$
$$x_{51} = 26.1804246396561$$
$$x_{51} = 76.4454782703127$$
$$x_{51} = -62.8317686516205$$
$$x_{51} = 63.8791322982152$$
$$x_{51} = 24.0861176040221$$
$$x_{51} = 30.3690901502898$$
$$x_{51} = 70.1623036339133$$
$$x_{51} = -81.6813590371603$$
$$x_{51} = -50.2653505632743$$
$$x_{51} = -94.2477420841309$$
$$x_{51} = -37.698877411849$$
Decrece en los intervalos
$$\left[100.530997894843, \infty\right)$$
Crece en los intervalos
$$\left(-\infty, -99.4837336857622\right]$$