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$$\left(\left(\left(\sin{\left(3 x \right)} + \cos{\left(3 x \right)}\right) e^{x} + 16 \cos{\left(x \right)}\right) + \sin{\left(x \right)}\right) e^{x} + \left(\left(- 3 \sin{\left(3 x \right)} + 3 \cos{\left(3 x \right)}\right) e^{x} + \left(\sin{\left(3 x \right)} + \cos{\left(3 x \right)}\right) e^{x} - 16 \sin{\left(x \right)} + \cos{\left(x \right)}\right) e^{x} = 0$$
Resolvermos esta ecuaciónRaíces de esta ecuación
$$x_{1} = -80.8335920199412$$
$$x_{2} = -55.7008507912229$$
$$x_{3} = -39.9928875232739$$
$$x_{4} = -30.5681095625045$$
$$x_{5} = -99.68314794148$$
$$x_{6} = -96.5415552878902$$
$$x_{7} = -21.1433316018712$$
$$x_{8} = -52.5592581376331$$
$$x_{9} = -11.7185553269422$$
$$x_{10} = -71.4088140591718$$
$$x_{11} = -18.0017389512938$$
$$x_{12} = -90.2583699807106$$
$$x_{13} = 7.78855853458055$$
$$x_{14} = -46.2760728304535$$
$$x_{15} = -5.43626931437669$$
$$x_{16} = -27.426516908915$$
$$x_{17} = -8.57699999873181$$
$$x_{18} = -24.2849242553308$$
$$x_{19} = -61.9840360984025$$
$$x_{20} = -43.1344801768637$$
$$x_{21} = -65.1256287519923$$
$$x_{22} = -36.8512948696841$$
$$x_{23} = -77.6919993663514$$
$$x_{24} = 5.68881445086257$$
$$x_{25} = 14.0713691222027$$
$$x_{26} = -14.8601463674135$$
$$x_{27} = -74.5504067127616$$
$$x_{28} = -83.975184673531$$
$$x_{29} = -93.3999626343004$$
$$x_{30} = 0.633286585380397$$
$$x_{31} = -68.267221405582$$
$$x_{32} = -87.1167773271208$$
$$x_{33} = 11.9769640833544$$
$$x_{34} = -2.31370196214823$$
$$x_{35} = 3.61403731599096$$
$$x_{36} = -58.8424434448127$$
$$x_{37} = -49.4176654840433$$
$$x_{38} = 9.8826069836513$$
$$x_{39} = -33.7097022160943$$
Signos de extremos en los puntos:
(-80.83359201994122, 8.88932116322487e-35)
(-55.70085079122287, 7.30936127309036e-24)
(-39.99288752327391, -4.85021730835731e-17)
(-30.56810956250454, 6.01021846770254e-13)
(-99.68314794147997, 5.78909230248975e-43)
(-96.54155528789019, -1.33963605594704e-41)
(-21.143331601871203, -7.44765104992703e-9)
(-52.55925813763308, -1.69143682562524e-22)
(-11.718555326942232, 9.22886513582704e-5)
(-71.40881405917185, -1.10153337106143e-30)
(-18.00173895129383, 1.72343803724332e-7)
(-90.2583699807106, -7.17363929399746e-39)
(7.7885585345805515, -6840393.55260736)
(-46.276072830453494, -9.05750305969614e-20)
(-5.436269314376695, 0.0494148483212453)
(-27.426516908914987, -1.39080618216954e-11)
(-8.576999998731813, -0.00213561437711268)
(-24.28492425533082, 3.21842183733343e-10)
(-61.984036098402456, 1.36498135828605e-26)
(-43.1344801768637, 2.09596894324886e-18)
(-65.12562875199225, -5.8986192848546e-28)
(-36.85129486968411, 1.12237387934882e-15)
(-77.69199936635142, -2.05705048752247e-33)
(5.688814450862571, -100038.045586924)
(14.071369122202722, -1962905116030.03)
(-14.860146367413476, -3.98815495796951e-6)
(-74.55040671276163, 4.76015730618661e-32)
(-83.97518467353102, -3.8414239816802e-36)
(-93.3999626343004, 3.10001062104591e-40)
(0.6332865853803971, 27.6223095196631)
(-68.26722140558205, 2.54902451644817e-29)
(-87.1167773271208, 1.66002981960823e-37)
(11.976964083354392, -29764723059.854)
(-2.3137019621482326, -1.14140221205263)
(3.614037315990961, -2117.64241195028)
(-58.842443444812666, -3.15866140615709e-25)
(-49.41766548404328, 3.91410196895576e-21)
(9.882606983651302, -451691217.278745)
(-33.70970221609432, -2.59725089610712e-14)
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:
$$x_{1} = -39.9928875232739$$
$$x_{2} = -96.5415552878902$$
$$x_{3} = -21.1433316018712$$
$$x_{4} = -52.5592581376331$$
$$x_{5} = -71.4088140591718$$
$$x_{6} = -90.2583699807106$$
$$x_{7} = 7.78855853458055$$
$$x_{8} = -46.2760728304535$$
$$x_{9} = -27.426516908915$$
$$x_{10} = -8.57699999873181$$
$$x_{11} = -65.1256287519923$$
$$x_{12} = -77.6919993663514$$
$$x_{13} = 5.68881445086257$$
$$x_{14} = 14.0713691222027$$
$$x_{15} = -14.8601463674135$$
$$x_{16} = -83.975184673531$$
$$x_{17} = 11.9769640833544$$
$$x_{18} = -2.31370196214823$$
$$x_{19} = 3.61403731599096$$
$$x_{20} = -58.8424434448127$$
$$x_{21} = 9.8826069836513$$
$$x_{22} = -33.7097022160943$$
Puntos máximos de la función:
$$x_{22} = -80.8335920199412$$
$$x_{22} = -55.7008507912229$$
$$x_{22} = -30.5681095625045$$
$$x_{22} = -99.68314794148$$
$$x_{22} = -11.7185553269422$$
$$x_{22} = -18.0017389512938$$
$$x_{22} = -5.43626931437669$$
$$x_{22} = -24.2849242553308$$
$$x_{22} = -61.9840360984025$$
$$x_{22} = -43.1344801768637$$
$$x_{22} = -36.8512948696841$$
$$x_{22} = -74.5504067127616$$
$$x_{22} = -93.3999626343004$$
$$x_{22} = 0.633286585380397$$
$$x_{22} = -68.267221405582$$
$$x_{22} = -87.1167773271208$$
$$x_{22} = -49.4176654840433$$
Decrece en los intervalos
$$\left[14.0713691222027, \infty\right)$$
Crece en los intervalos
$$\left(-\infty, -96.5415552878902\right]$$