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$$\left(- 2 \sin{\left(2 x \right)} + 2 \cos{\left(2 x \right)}\right) e^{- x} - \left(\sin{\left(2 x \right)} + \cos{\left(2 x \right)}\right) e^{- x} - 2 \sin{\left(x \right)} + \cos{\left(x \right)} = 0$$
Resolvermos esta ecuaciónRaíces de esta ecuación
$$x_{1} = 44.4459447592579$$
$$x_{2} = 3.62801422609082$$
$$x_{3} = -15.5470880094102$$
$$x_{4} = 66.4370933343865$$
$$x_{5} = 69.5786859879763$$
$$x_{6} = 28.7379814913092$$
$$x_{7} = -28.1134586051099$$
$$x_{8} = 0.255701375162867$$
$$x_{9} = 72.7202786415661$$
$$x_{10} = 38.1627594520783$$
$$x_{11} = 31.8795741448987$$
$$x_{12} = 25.596388837713$$
$$x_{13} = -17.117884305128$$
$$x_{14} = 88.428241909515$$
$$x_{15} = 9.88846643296898$$
$$x_{16} = -21.8302732979651$$
$$x_{17} = 91.5698345631048$$
$$x_{18} = 19.3132035272422$$
$$x_{19} = 63.2955006807967$$
$$x_{20} = -13.9762919513053$$
$$x_{21} = 13.0300164576432$$
$$x_{22} = 57.0123153736171$$
$$x_{23} = -31.2550512586996$$
$$x_{24} = -29.6842549319047$$
$$x_{25} = -7.69326019908088$$
$$x_{26} = 22.4547961842719$$
$$x_{27} = 47.5875374128477$$
$$x_{28} = -23.4010696247019$$
$$x_{29} = 94.7114272166946$$
$$x_{30} = 16.1716109532536$$
$$x_{31} = 97.8530198702844$$
$$x_{32} = 35.0211667984885$$
$$x_{33} = -20.2594769716719$$
$$x_{34} = 100.994612523874$$
$$x_{35} = -9.26391267581802$$
$$x_{36} = 75.8618712951559$$
$$x_{37} = 79.0034639487456$$
$$x_{38} = 53.8707227200273$$
$$x_{39} = -1.484665633778$$
$$x_{40} = 82.1450566023354$$
$$x_{41} = 6.74588907568972$$
$$x_{42} = 85.2866492559252$$
$$x_{43} = 41.3043521056681$$
$$x_{44} = -6.12207892521095$$
$$x_{45} = 50.7291300664375$$
$$x_{46} = 60.1539080272069$$
Signos de extremos en los puntos:
(44.44594475925791, 2.23606797749979)
(3.6280142260908157, -2.1985722071687)
(-15.547088009410185, 7146187.15002582)
(66.43709333438646, -2.23606797749979)
(69.57868598797626, 2.23606797749979)
(28.73798149130921, -2.23606797749933)
(-28.113458605109884, 2049179161217.76)
(0.255701375162867, 3.24217432825651)
(72.72027864156605, -2.23606797749979)
(38.162759452078326, 2.23606797749979)
(31.879574144898726, 2.23606797749981)
(25.596388837712993, 2.2360679775105)
(-17.117884305128037, -34376581.2458983)
(88.42824190951502, 2.23606797749979)
(9.888466432968976, -2.23599691704751)
(-21.83027329796508, 3826724728.45321)
(91.5698345631048, -2.23606797749979)
(19.31320352724218, 2.23606798323448)
(63.29550068079667, 2.23606797749979)
(-13.976291951305344, -1485547.46768316)
(13.030016457643212, 2.23607104838452)
(57.012315373617085, 2.23606797749979)
(-31.25505125869961, 47419425119288.2)
(-29.684254931904672, -9857530004593.2)
(-7.6932601990808775, -2774.84046322185)
(22.454796184271853, -2.23606797725197)
(47.5875374128477, -2.23606797749979)
(-23.40106962470194, -18408372759.0055)
(94.7114272166946, 2.23606797749979)
(16.171610953253577, -2.23606784479499)
(97.8530198702844, -2.23606797749979)
(35.02116679848853, -2.23606797749979)
(-20.259476971671944, -795497916.472251)
(100.9946125238742, 2.23606797749979)
(-9.263912675818018, 13342.9648847032)
(75.86187129515585, 2.23606797749979)
(79.00346394874563, -2.23606797749979)
(53.87072272002729, -2.23606797749979)
(-1.4846656337780049, -5.92893219327708)
(82.14505660233543, 2.23606797749979)
(6.745889075689718, 2.23771340654961)
(85.28664925592523, -2.23606797749979)
(41.304352105668116, -2.23606797749979)
(-6.1220789252109515, 578.828461909566)
(50.7291300664375, 2.23606797749979)
(60.153908027206874, -2.23606797749979)
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:
$$x_{1} = 3.62801422609082$$
$$x_{2} = 66.4370933343865$$
$$x_{3} = 28.7379814913092$$
$$x_{4} = 72.7202786415661$$
$$x_{5} = -17.117884305128$$
$$x_{6} = 9.88846643296898$$
$$x_{7} = 91.5698345631048$$
$$x_{8} = -13.9762919513053$$
$$x_{9} = -29.6842549319047$$
$$x_{10} = -7.69326019908088$$
$$x_{11} = 22.4547961842719$$
$$x_{12} = 47.5875374128477$$
$$x_{13} = -23.4010696247019$$
$$x_{14} = 16.1716109532536$$
$$x_{15} = 97.8530198702844$$
$$x_{16} = 35.0211667984885$$
$$x_{17} = -20.2594769716719$$
$$x_{18} = 79.0034639487456$$
$$x_{19} = 53.8707227200273$$
$$x_{20} = -1.484665633778$$
$$x_{21} = 85.2866492559252$$
$$x_{22} = 41.3043521056681$$
$$x_{23} = 60.1539080272069$$
Puntos máximos de la función:
$$x_{23} = 44.4459447592579$$
$$x_{23} = -15.5470880094102$$
$$x_{23} = 69.5786859879763$$
$$x_{23} = -28.1134586051099$$
$$x_{23} = 0.255701375162867$$
$$x_{23} = 38.1627594520783$$
$$x_{23} = 31.8795741448987$$
$$x_{23} = 25.596388837713$$
$$x_{23} = 88.428241909515$$
$$x_{23} = -21.8302732979651$$
$$x_{23} = 19.3132035272422$$
$$x_{23} = 63.2955006807967$$
$$x_{23} = 13.0300164576432$$
$$x_{23} = 57.0123153736171$$
$$x_{23} = -31.2550512586996$$
$$x_{23} = 94.7114272166946$$
$$x_{23} = 100.994612523874$$
$$x_{23} = -9.26391267581802$$
$$x_{23} = 75.8618712951559$$
$$x_{23} = 82.1450566023354$$
$$x_{23} = 6.74588907568972$$
$$x_{23} = -6.12207892521095$$
$$x_{23} = 50.7291300664375$$
Decrece en los intervalos
$$\left[97.8530198702844, \infty\right)$$
Crece en los intervalos
$$\left(-\infty, -29.6842549319047\right]$$