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$$8 x \sin{\left(2 x \right)} - 6 x \cos{\left(2 x \right)} - \left(- x - 1\right) e^{- x} - \frac{7 \sin{\left(2 x \right)}}{5} + \frac{24 \cos{\left(2 x \right)}}{5} - e^{- x} = 0$$
Resolvermos esta ecuaciónRaíces de esta ecuación
$$x_{1} = 82.0013213504849$$
$$x_{2} = 97.7095813485123$$
$$x_{3} = 42.7297078266193$$
$$x_{4} = 30.1618409233784$$
$$x_{5} = 96.1387597304536$$
$$x_{6} = 67.8637692055864$$
$$x_{7} = 86.7138106903959$$
$$x_{8} = 36.4459048063813$$
$$x_{9} = 88.2846380786111$$
$$x_{10} = 39.5878310801846$$
$$x_{11} = 61.5803555516686$$
$$x_{12} = 102.422041529783$$
$$x_{13} = 66.2929198749139$$
$$x_{14} = 5.00195544130954$$
$$x_{15} = 52.1551311077314$$
$$x_{16} = 9.7304545664145$$
$$x_{17} = 50.5842440614957$$
$$x_{18} = 60.0094946161975$$
$$x_{19} = 16.020111993054$$
$$x_{20} = 80.4304889440277$$
$$x_{21} = 23.8773066554791$$
$$x_{22} = 83.5721523940922$$
$$x_{23} = -1.04531244075747$$
$$x_{24} = 64.7220679553212$$
$$x_{25} = 45.871545313038$$
$$x_{26} = 14.4482416526545$$
$$x_{27} = 31.7328899347876$$
$$x_{28} = 53.7260128090016$$
$$x_{29} = 6.58061170058247$$
$$x_{30} = 3.41184475352026$$
$$x_{31} = 1.79722028457545$$
$$x_{32} = 94.5679372686185$$
$$x_{33} = 17.5917859387702$$
$$x_{34} = 58.4386301832932$$
$$x_{35} = 8.15641807249072$$
$$x_{36} = 28.59076374588$$
$$x_{37} = 75.7179826948227$$
$$x_{38} = 89.8554643759487$$
$$x_{39} = 44.3006309504545$$
$$x_{40} = 22.3060521347805$$
$$x_{41} = 38.0168749099347$$
$$x_{42} = 20.7347267942285$$
$$x_{43} = 74.1471439479031$$
$$x_{44} = 72.5763033545058$$
Signos de extremos en los puntos:
(82.00132135048491, -408.018555016927)
(97.70958134851229, -486.557926268775)
(42.72970782661926, 211.671572090084)
(30.16184092337843, 148.84196321498)
(96.13875973045359, 478.703982571177)
(67.86376920558638, 337.33329810323)
(86.71381069039586, 431.580349382289)
(36.445904806381265, 180.256572045683)
(88.28463807861112, -439.434284424917)
(39.5878310801846, 195.964034928584)
(61.58035555166859, 305.917714076825)
(102.4220415297831, 510.119764370742)
(66.29291987491392, -329.479395972791)
(5.001955441309536, 23.1790590108791)
(52.155131107731364, 258.794493970511)
(9.730454566414501, -46.7573749584005)
(50.58424406149571, -250.940648409015)
(60.009494616197514, -298.063829352476)
(16.02011199305398, -78.1629712162921)
(80.43048894402772, 400.16462750139)
(23.877306655479092, 117.428059742964)
(83.57215239409223, 415.872484576662)
(-1.0453124407574717, -8.09116397932016)
(64.72206795532122, 321.625497725504)
(45.87154531303799, 227.379168133157)
(14.448241652654461, 70.3105896305165)
(31.73288993478761, -156.695565873901)
(53.726012809001595, -266.64834754869)
(6.580611700582473, -31.0715280641441)
(3.4118447535202554, -15.5361810809344)
(1.7972202845754457, 7.15385460972602)
(94.56793726861854, -470.850040139209)
(17.591785938770194, 86.0156347557838)
(58.4386301832932, 290.2099498739)
(8.156418072490723, 38.9050074363988)
(28.59076374587995, -140.988402792998)
(75.71798269482274, -376.602858498971)
(89.85546437594871, 447.288221103806)
(44.30063095045447, -219.525363541552)
(22.306052134780472, -109.574765235038)
(38.01687490993474, -188.110293039044)
(20.734726794228454, 101.721576868008)
(74.14714394790312, 368.748940493723)
(72.57630335450584, -360.895025258062)
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:
$$x_{1} = 82.0013213504849$$
$$x_{2} = 97.7095813485123$$
$$x_{3} = 88.2846380786111$$
$$x_{4} = 66.2929198749139$$
$$x_{5} = 9.7304545664145$$
$$x_{6} = 50.5842440614957$$
$$x_{7} = 60.0094946161975$$
$$x_{8} = 16.020111993054$$
$$x_{9} = -1.04531244075747$$
$$x_{10} = 31.7328899347876$$
$$x_{11} = 53.7260128090016$$
$$x_{12} = 6.58061170058247$$
$$x_{13} = 3.41184475352026$$
$$x_{14} = 94.5679372686185$$
$$x_{15} = 28.59076374588$$
$$x_{16} = 75.7179826948227$$
$$x_{17} = 44.3006309504545$$
$$x_{18} = 22.3060521347805$$
$$x_{19} = 38.0168749099347$$
$$x_{20} = 72.5763033545058$$
Puntos máximos de la función:
$$x_{20} = 42.7297078266193$$
$$x_{20} = 30.1618409233784$$
$$x_{20} = 96.1387597304536$$
$$x_{20} = 67.8637692055864$$
$$x_{20} = 86.7138106903959$$
$$x_{20} = 36.4459048063813$$
$$x_{20} = 39.5878310801846$$
$$x_{20} = 61.5803555516686$$
$$x_{20} = 102.422041529783$$
$$x_{20} = 5.00195544130954$$
$$x_{20} = 52.1551311077314$$
$$x_{20} = 80.4304889440277$$
$$x_{20} = 23.8773066554791$$
$$x_{20} = 83.5721523940922$$
$$x_{20} = 64.7220679553212$$
$$x_{20} = 45.871545313038$$
$$x_{20} = 14.4482416526545$$
$$x_{20} = 1.79722028457545$$
$$x_{20} = 17.5917859387702$$
$$x_{20} = 58.4386301832932$$
$$x_{20} = 8.15641807249072$$
$$x_{20} = 89.8554643759487$$
$$x_{20} = 20.7347267942285$$
$$x_{20} = 74.1471439479031$$
Decrece en los intervalos
$$\left[97.7095813485123, \infty\right)$$
Crece en los intervalos
$$\left(-\infty, -1.04531244075747\right]$$