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$$- x \sin{\left(x \right)} \cos{\left(x \right)} + \frac{\cos^{2}{\left(x \right)}}{2} + 2 \cos{\left(x \right)} = 0$$
Resolvermos esta ecuaciónRaíces de esta ecuación
$$x_{1} = -44.0390771234017$$
$$x_{2} = 23.5619449019235$$
$$x_{3} = 2.3860860459443$$
$$x_{4} = -86.3937979737193$$
$$x_{5} = 65.9506975390986$$
$$x_{6} = -53.3789667537027$$
$$x_{7} = 44.0390771234017$$
$$x_{8} = -95.8185759344887$$
$$x_{9} = 56.5928487077727$$
$$x_{10} = 21.9226189316584$$
$$x_{11} = -83.2522053201295$$
$$x_{12} = 95.8185759344887$$
$$x_{13} = 303.163691071415$$
$$x_{14} = -97.373966514501$$
$$x_{15} = -94.274299213244$$
$$x_{16} = 37.7653294920198$$
$$x_{17} = 9.26136941301364$$
$$x_{18} = 45.553093477052$$
$$x_{19} = 20.4203522483337$$
$$x_{20} = -80.1106126665397$$
$$x_{21} = 72.2358627380718$$
$$x_{22} = -14.1371669411541$$
$$x_{23} = 81.7120061622563$$
$$x_{24} = -29.845130209103$$
$$x_{25} = 70.6858347057703$$
$$x_{26} = -102.101761241668$$
$$x_{27} = -15.6115829776934$$
$$x_{28} = 48.6946861306418$$
$$x_{29} = -81.7120061622563$$
$$x_{30} = -31.4953367711689$$
$$x_{31} = -20.4203522483337$$
$$x_{32} = -61.261056745001$$
$$x_{33} = 26.7035375555132$$
$$x_{34} = 94.274299213244$$
$$x_{35} = -9.26136941301364$$
$$x_{36} = -87.993007178388$$
$$x_{37} = -51.8362787842316$$
$$x_{38} = 15.6115829776934$$
$$x_{39} = -42.4115008234622$$
$$x_{40} = -17.2787595947439$$
$$x_{41} = -28.2211320612647$$
$$x_{42} = 51.8362787842316$$
$$x_{43} = 73.8274273593601$$
$$x_{44} = -65.9506975390986$$
$$x_{45} = 34.5140312012932$$
$$x_{46} = 59.665114800435$$
$$x_{47} = 29.845130209103$$
$$x_{48} = -58.1194640914112$$
$$x_{49} = 32.9867228626928$$
$$x_{50} = 42.4115008234622$$
$$x_{51} = 12.7627599249538$$
$$x_{52} = -23.5619449019235$$
$$x_{53} = -64.4026493985908$$
$$x_{54} = -73.8274273593601$$
$$x_{55} = -89.5353906273091$$
$$x_{56} = -72.2358627380718$$
$$x_{57} = 64.4026493985908$$
$$x_{58} = 80.1106126665397$$
$$x_{59} = 78.5207107750708$$
$$x_{60} = -50.3151774380626$$
$$x_{61} = -39.2699081698724$$
$$x_{62} = 28.2211320612647$$
$$x_{63} = -37.7653294920198$$
$$x_{64} = 36.1283155162826$$
$$x_{65} = -45.553093477052$$
$$x_{66} = -75.4313688242127$$
$$x_{67} = 14.1371669411541$$
$$x_{68} = 1.95517406323303$$
$$x_{69} = 50.3151774380626$$
$$x_{70} = 87.993007178388$$
$$x_{71} = 144.530559790087$$
$$x_{72} = 92.6769832808989$$
$$x_{73} = 67.5442420521806$$
$$x_{74} = -21.9226189316584$$
$$x_{75} = 58.1194640914112$$
$$x_{76} = 6.66212078172724$$
$$x_{77} = -7.85398163397448$$
$$x_{78} = 7.85398163397448$$
$$x_{79} = 100.555827750706$$
$$x_{80} = -67.5442420521806$$
$$x_{81} = 89.5353906273091$$
$$x_{82} = 86.3937979737193$$
$$x_{83} = -36.1283155162826$$
$$x_{84} = -59.665114800435$$
$$x_{85} = 4.71238898038469$$
$$x_{86} = 1.5707963267949$$
$$x_{87} = -1.95517406323303$$
Signos de extremos en los puntos:
(-44.03907712340174, -22.0621235268108)
(23.56194490192345, -2)
(2.386086045944296, 2.00347724185052)
(-86.39379797371932, 2)
(65.95069753909861, 33.0037800787516)
(-53.37896675370266, -26.7246114216225)
(44.03907712340174, 22.0621235268108)
(-95.81857593448869, -2)
(56.59284870777266, 28.3295600570462)
(21.92261893165838, 11.0468643042567)
(-83.25220532012952, -2)
(95.81857593448869, 2)
(303.16369107141503, 2)
(-97.37396651450105, -48.7062392219801)
(-94.27429921324396, -47.1570393104567)
(37.76532949201978, 18.9323279509052)
(9.261369413013638, 4.8334957711568)
(45.553093477052, 2)
(20.420352248333657, 2)
(-80.11061266653972, 2)
(72.23586273807183, 36.1438887513725)
(-14.137166941154069, -2)
(81.71200616225626, 40.878950957149)
(-29.845130209103036, 2)
(70.68583470577035, 2)
(-102.10176124166829, -2)
(-15.611582977693413, -7.92596876727007)
(48.6946861306418, -2)
(-81.71200616225626, -40.878950957149)
(-31.4953367711689, -15.8072259831523)
(-20.420352248333657, -2)
(-61.26105674500097, 2)
(26.703537555513243, 2)
(94.27429921324396, 47.1570393104567)
(-9.261369413013638, -4.8334957711568)
(-87.99300717838803, -44.0178132471365)
(-51.83627878423159, -2)
(15.611582977693413, 7.92596876727007)
(-42.411500823462205, 2)
(-17.278759594743864, 2)
(-28.221132061264726, -14.1770181299482)
(51.83627878423159, 2)
(73.82742735936014, -2)
(-65.95069753909861, -33.0037800787516)
(34.51403120129323, 17.3113481774677)
(59.66511480043501, 29.8639841229746)
(29.845130209103036, -2)
(-58.119464091411174, -2)
(32.98672286269283, 2)
(42.411500823462205, -2)
(12.762759924953802, 6.52866467541177)
(-23.56194490192345, 2)
(-64.40264939859077, -2)
(-73.82742735936014, 2)
(-89.53539062730911, -2)
(-72.23586273807183, -36.1438887513725)
(64.40264939859077, 2)
(80.11061266653972, -2)
(78.52071077507081, 39.2842350188297)
(-50.31517743806264, -25.1948599469259)
(-39.269908169872416, -2)
(28.221132061264726, 14.1770181299482)
(-37.76532949201978, -18.9323279509052)
(36.12831551628262, -2)
(-45.553093477052, -2)
(-75.43136882421273, -37.7405432646497)
(14.137166941154069, 2)
(1.9551740632330274, 1.99152413666373)
(50.31517743806264, 25.1948599469259)
(87.99300717838803, 44.0178132471365)
(144.53055979008684, 72.278253188722)
(92.6769832808989, -2)
(67.54424205218055, -2)
(-21.92261893165838, -11.0468643042567)
(58.119464091411174, 2)
(6.662120781727237, 3.61506997914071)
(-7.853981633974483, -2)
(7.853981633974483, 2)
(100.55582775070604, 50.29656100199)
(-67.54424205218055, 2)
(89.53539062730911, 2)
(86.39379797371932, -2)
(-36.12831551628262, 2)
(-59.66511480043501, -29.8639841229746)
(4.71238898038469, -2)
(1.5707963267948966, 2)
(-1.9551740632330274, -1.99152413666373)
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:
$$x_{1} = -44.0390771234017$$
$$x_{2} = 23.5619449019235$$
$$x_{3} = -53.3789667537027$$
$$x_{4} = 95.8185759344887$$
$$x_{5} = 303.163691071415$$
$$x_{6} = -97.373966514501$$
$$x_{7} = -94.274299213244$$
$$x_{8} = 45.553093477052$$
$$x_{9} = 20.4203522483337$$
$$x_{10} = 70.6858347057703$$
$$x_{11} = -15.6115829776934$$
$$x_{12} = 48.6946861306418$$
$$x_{13} = -81.7120061622563$$
$$x_{14} = -31.4953367711689$$
$$x_{15} = 26.7035375555132$$
$$x_{16} = -9.26136941301364$$
$$x_{17} = -87.993007178388$$
$$x_{18} = -28.2211320612647$$
$$x_{19} = 51.8362787842316$$
$$x_{20} = 73.8274273593601$$
$$x_{21} = -65.9506975390986$$
$$x_{22} = 29.845130209103$$
$$x_{23} = 32.9867228626928$$
$$x_{24} = 42.4115008234622$$
$$x_{25} = -72.2358627380718$$
$$x_{26} = 64.4026493985908$$
$$x_{27} = 80.1106126665397$$
$$x_{28} = -50.3151774380626$$
$$x_{29} = -37.7653294920198$$
$$x_{30} = 36.1283155162826$$
$$x_{31} = -75.4313688242127$$
$$x_{32} = 14.1371669411541$$
$$x_{33} = 1.95517406323303$$
$$x_{34} = 92.6769832808989$$
$$x_{35} = 67.5442420521806$$
$$x_{36} = -21.9226189316584$$
$$x_{37} = 58.1194640914112$$
$$x_{38} = 7.85398163397448$$
$$x_{39} = 89.5353906273091$$
$$x_{40} = 86.3937979737193$$
$$x_{41} = -59.665114800435$$
$$x_{42} = 4.71238898038469$$
Puntos máximos de la función:
$$x_{42} = 2.3860860459443$$
$$x_{42} = -86.3937979737193$$
$$x_{42} = 65.9506975390986$$
$$x_{42} = 44.0390771234017$$
$$x_{42} = -95.8185759344887$$
$$x_{42} = 56.5928487077727$$
$$x_{42} = 21.9226189316584$$
$$x_{42} = -83.2522053201295$$
$$x_{42} = 37.7653294920198$$
$$x_{42} = 9.26136941301364$$
$$x_{42} = -80.1106126665397$$
$$x_{42} = 72.2358627380718$$
$$x_{42} = -14.1371669411541$$
$$x_{42} = 81.7120061622563$$
$$x_{42} = -29.845130209103$$
$$x_{42} = -102.101761241668$$
$$x_{42} = -20.4203522483337$$
$$x_{42} = -61.261056745001$$
$$x_{42} = 94.274299213244$$
$$x_{42} = -51.8362787842316$$
$$x_{42} = 15.6115829776934$$
$$x_{42} = -42.4115008234622$$
$$x_{42} = -17.2787595947439$$
$$x_{42} = 34.5140312012932$$
$$x_{42} = 59.665114800435$$
$$x_{42} = -58.1194640914112$$
$$x_{42} = 12.7627599249538$$
$$x_{42} = -23.5619449019235$$
$$x_{42} = -64.4026493985908$$
$$x_{42} = -73.8274273593601$$
$$x_{42} = -89.5353906273091$$
$$x_{42} = 78.5207107750708$$
$$x_{42} = -39.2699081698724$$
$$x_{42} = 28.2211320612647$$
$$x_{42} = -45.553093477052$$
$$x_{42} = 50.3151774380626$$
$$x_{42} = 87.993007178388$$
$$x_{42} = 144.530559790087$$
$$x_{42} = 6.66212078172724$$
$$x_{42} = -7.85398163397448$$
$$x_{42} = 100.555827750706$$
$$x_{42} = -67.5442420521806$$
$$x_{42} = -36.1283155162826$$
$$x_{42} = 1.5707963267949$$
$$x_{42} = -1.95517406323303$$
Decrece en los intervalos
$$\left[303.163691071415, \infty\right)$$
Crece en los intervalos
$$\left(-\infty, -97.373966514501\right]$$