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$$- \frac{x e^{x}}{15} - \frac{x \sin{\left(2 x \right)}}{8} + \frac{3 x \cos{\left(2 x \right)}}{16} - \frac{19 e^{x}}{225} + \frac{3 \sin{\left(2 x \right)}}{32} + \frac{\cos{\left(2 x \right)}}{16} = 0$$
Resolvermos esta ecuaciónRaíces de esta ecuación
$$x_{1} = -98.471310515166$$
$$x_{2} = -57.6324049583308$$
$$x_{3} = -49.7791076141865$$
$$x_{4} = -21.5113713815282$$
$$x_{5} = -78.0516224426785$$
$$x_{6} = -1.26727874692502$$
$$x_{7} = -85.9053112601801$$
$$x_{8} = -93.759049130088$$
$$x_{9} = -4.27773547300515$$
$$x_{10} = -92.1882982336104$$
$$x_{11} = -40.3555022601813$$
$$x_{12} = -29.3622468594312$$
$$x_{13} = -48.2084748932662$$
$$x_{14} = -15.232972316552$$
$$x_{15} = -70.1979991389905$$
$$x_{16} = -76.48089189509$$
$$x_{17} = -71.7687175264203$$
$$x_{18} = -34.0734588902844$$
$$x_{19} = -5.83486727420224$$
$$x_{20} = -7.39625925191978$$
$$x_{21} = -13.6640579391882$$
$$x_{22} = -32.5030169881147$$
$$x_{23} = -19.9414894366411$$
$$x_{24} = -79.6223555853468$$
$$x_{25} = -51.3497503415931$$
$$x_{26} = -100.042066981211$$
$$x_{27} = -41.9260665567007$$
$$x_{28} = -73.3394392520075$$
$$x_{29} = -87.4760553327053$$
$$x_{30} = -84.3345691340066$$
$$x_{31} = -56.0617301548025$$
$$x_{32} = -43.4966476048778$$
$$x_{33} = -54.491062355794$$
$$x_{34} = -18.3717635420857$$
$$x_{35} = -95.3298015235949$$
$$x_{36} = -62.3444661032045$$
$$x_{37} = -27.7919314668975$$
$$x_{38} = -35.6439320112096$$
$$x_{39} = -65.4858664072384$$
$$x_{40} = -26.2216736363854$$
$$x_{41} = -12.095631350343$$
$$x_{42} = -63.9151638920383$$
Signos de extremos en los puntos:
(-98.47131051516602, 11.094961950228)
(-57.63240495833079, 6.49339910935805)
(-49.77910761418651, -5.60850224243671)
(-21.511371381528207, -2.42310654875779)
(-78.05162244267855, -8.79416727257782)
(-1.2672787469250184, 0.151610881629222)
(-85.90531126018008, 9.67908619728926)
(-93.75904913008796, -10.5640078856903)
(-4.277735473005145, 0.482596830381681)
(-92.18829823361038, 10.3870233608172)
(-40.35550226018127, -4.54664580753522)
(-29.362246859431202, 3.30786689114382)
(-48.20847489326621, 5.43152437629713)
(-15.232972316552027, -1.71542787689833)
(-70.19799913899048, 7.90925203908546)
(-76.48089189509001, 8.61718389419625)
(-71.76871752642033, -8.08623473232497)
(-34.07345889028443, -3.83876181786984)
(-5.834867274202241, -0.653910821066159)
(-7.396259251919782, 0.831764568173039)
(-13.664057939188218, 1.53854826674003)
(-32.50301698811466, 3.66179470627321)
(-19.941489436641092, 2.2461710188053)
(-79.62235558534682, 8.97115079717272)
(-51.349750341593136, 5.78548067245148)
(-100.04206698121065, -11.2719467888936)
(-41.92606655670071, 4.72361981765251)
(-73.33943925200752, 8.26321761364821)
(-87.4760553327053, -9.85607033769324)
(-84.33456913400661, -9.50210216654568)
(-56.06173015480246, -6.31641887188332)
(-43.49664760487781, -4.90059477183981)
(-54.49106235579396, 6.13943902909895)
(-18.37176354208566, -2.0692442749945)
(-95.32980152359485, 10.7409924949071)
(-62.344466103204496, -7.02434189164963)
(-27.79193146689746, -3.13090691143212)
(-35.6439320112096, 4.01573068917917)
(-65.48586640723843, -7.37830522319598)
(-26.2216736363854, 2.9539501772242)
(-12.095631350342984, -1.36168944603642)
(-63.91516389203826, 7.20132342426838)
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:
$$x_{1} = -49.7791076141865$$
$$x_{2} = -21.5113713815282$$
$$x_{3} = -78.0516224426785$$
$$x_{4} = -93.759049130088$$
$$x_{5} = -40.3555022601813$$
$$x_{6} = -15.232972316552$$
$$x_{7} = -71.7687175264203$$
$$x_{8} = -34.0734588902844$$
$$x_{9} = -5.83486727420224$$
$$x_{10} = -100.042066981211$$
$$x_{11} = -87.4760553327053$$
$$x_{12} = -84.3345691340066$$
$$x_{13} = -56.0617301548025$$
$$x_{14} = -43.4966476048778$$
$$x_{15} = -18.3717635420857$$
$$x_{16} = -62.3444661032045$$
$$x_{17} = -27.7919314668975$$
$$x_{18} = -65.4858664072384$$
$$x_{19} = -12.095631350343$$
Puntos máximos de la función:
$$x_{19} = -98.471310515166$$
$$x_{19} = -57.6324049583308$$
$$x_{19} = -1.26727874692502$$
$$x_{19} = -85.9053112601801$$
$$x_{19} = -4.27773547300515$$
$$x_{19} = -92.1882982336104$$
$$x_{19} = -29.3622468594312$$
$$x_{19} = -48.2084748932662$$
$$x_{19} = -70.1979991389905$$
$$x_{19} = -76.48089189509$$
$$x_{19} = -7.39625925191978$$
$$x_{19} = -13.6640579391882$$
$$x_{19} = -32.5030169881147$$
$$x_{19} = -19.9414894366411$$
$$x_{19} = -79.6223555853468$$
$$x_{19} = -51.3497503415931$$
$$x_{19} = -41.9260665567007$$
$$x_{19} = -73.3394392520075$$
$$x_{19} = -54.491062355794$$
$$x_{19} = -95.3298015235949$$
$$x_{19} = -35.6439320112096$$
$$x_{19} = -26.2216736363854$$
$$x_{19} = -63.9151638920383$$
Decrece en los intervalos
$$\left[-5.83486727420224, \infty\right)$$
Crece en los intervalos
$$\left(-\infty, -100.042066981211\right]$$