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$$\sin{\left(x \right)} + 2 \cos{\left(x \right)} - e^{- x} = 0$$
Resolvermos esta ecuaciónRaíces de esta ecuación
$$x_{1} = 55.4415190468222$$
$$x_{2} = 42.875148432463$$
$$x_{3} = 52.2999263932324$$
$$x_{4} = 61.7247043540018$$
$$x_{5} = 80.5742602755405$$
$$x_{6} = 14.6008143462339$$
$$x_{7} = -0.387672850099208$$
$$x_{8} = 30.3087778181039$$
$$x_{9} = 89.9990382363099$$
$$x_{10} = 86.8574455827201$$
$$x_{11} = 5.17855714720614$$
$$x_{12} = 64.8662970075916$$
$$x_{13} = 71.1494823147711$$
$$x_{14} = 20.8839998569537$$
$$x_{15} = 74.2910749683609$$
$$x_{16} = 8.31752003309144$$
$$x_{17} = 68.0078896611814$$
$$x_{18} = 27.1671851645133$$
$$x_{19} = 93.1406308898997$$
$$x_{20} = 33.4503704716936$$
$$x_{21} = 46.0167410860528$$
$$x_{22} = 58.583111700412$$
$$x_{23} = 99.4238161970793$$
$$x_{24} = 11.4592266154144$$
$$x_{25} = 24.0255925109407$$
$$x_{26} = -0.387672850099237$$
$$x_{27} = 96.2822235434895$$
$$x_{28} = 36.5919631252834$$
$$x_{29} = 83.7158529291303$$
$$x_{30} = 49.1583337396426$$
$$x_{31} = 1.97217200998873$$
$$x_{32} = 39.7335557788732$$
$$x_{33} = 77.4326676219507$$
$$x_{34} = 17.7424072125569$$
Signos de extremos en los puntos:
(55.44151904682219, -1.23606797749979)
(42.875148432463014, -1.23606797749979)
(52.2999263932324, 3.23606797749979)
(61.72470435400177, -1.23606797749979)
(80.57426027554054, -1.23606797749979)
(14.600814346233902, 3.2360684334809)
(-0.38767285009920804, 0.791686353330576)
(30.308777818103874, -1.23606797749972)
(89.99903823630991, 3.23606797749979)
(86.85744558272012, -1.23606797749979)
(5.178557147206145, -1.23042474173664)
(64.86629700759157, 3.23606797749979)
(71.14948231477115, 3.23606797749979)
(20.88399985695365, 3.23606797835131)
(74.29107496836095, -1.23606797749979)
(8.31752003309144, 3.23631216488884)
(68.00788966118137, -1.23606797749979)
(27.167185164513338, 3.23606797750138)
(93.14063088989971, -1.23606797749979)
(33.45037047169363, 3.23606797749979)
(46.01674108605281, 3.23606797749979)
(58.58311170041198, 3.23606797749979)
(99.42381619707929, -1.23606797749979)
(11.459226615414424, -1.23605742580699)
(24.02559251094071, -1.23606797746299)
(-0.3876728500992374, 0.791686353330576)
(96.2822235434895, 3.23606797749979)
(36.59196312528343, -1.23606797749979)
(83.71585292913032, 3.23606797749979)
(49.1583337396426, -1.23606797749979)
(1.9721720099887343, 3.3708881574905)
(39.733555778873225, 3.23606797749979)
(77.43266762195074, 3.23606797749979)
(17.74240721255689, -1.23606795779506)
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:
$$x_{1} = 55.4415190468222$$
$$x_{2} = 42.875148432463$$
$$x_{3} = 61.7247043540018$$
$$x_{4} = 80.5742602755405$$
$$x_{5} = -0.387672850099208$$
$$x_{6} = 30.3087778181039$$
$$x_{7} = 86.8574455827201$$
$$x_{8} = 5.17855714720614$$
$$x_{9} = 74.2910749683609$$
$$x_{10} = 68.0078896611814$$
$$x_{11} = 93.1406308898997$$
$$x_{12} = 99.4238161970793$$
$$x_{13} = 11.4592266154144$$
$$x_{14} = 24.0255925109407$$
$$x_{15} = -0.387672850099237$$
$$x_{16} = 36.5919631252834$$
$$x_{17} = 49.1583337396426$$
$$x_{18} = 17.7424072125569$$
Puntos máximos de la función:
$$x_{18} = 52.2999263932324$$
$$x_{18} = 14.6008143462339$$
$$x_{18} = 89.9990382363099$$
$$x_{18} = 64.8662970075916$$
$$x_{18} = 71.1494823147711$$
$$x_{18} = 20.8839998569537$$
$$x_{18} = 8.31752003309144$$
$$x_{18} = 27.1671851645133$$
$$x_{18} = 33.4503704716936$$
$$x_{18} = 46.0167410860528$$
$$x_{18} = 58.583111700412$$
$$x_{18} = 96.2822235434895$$
$$x_{18} = 83.7158529291303$$
$$x_{18} = 1.97217200998873$$
$$x_{18} = 39.7335557788732$$
$$x_{18} = 77.4326676219507$$
Decrece en los intervalos
$$\left[99.4238161970793, \infty\right)$$
Crece en los intervalos
$$\left(-\infty, -0.387672850099237\right]$$