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$$- \cos{\left(x \right)} \operatorname{sign}{\left(\sin{\left(x \right)} \right)} + \cos{\left(x \right)} = 0$$
Resolvermos esta ecuaciónRaíces de esta ecuación
$$x_{1} = 90$$
$$x_{2} = 29.845130209103$$
$$x_{3} = -43.75$$
$$x_{4} = 78$$
$$x_{5} = 48.6946861306418$$
$$x_{6} = -7.85398163397448$$
$$x_{7} = 10.9955742875643$$
$$x_{8} = 70$$
$$x_{9} = -4$$
$$x_{10} = -100$$
$$x_{11} = -56$$
$$x_{12} = 67.5442420521806$$
$$x_{13} = -6$$
$$x_{14} = 38$$
$$x_{15} = -58.1194640914112$$
$$x_{16} = 46$$
$$x_{17} = 2$$
$$x_{18} = -36$$
$$x_{19} = 80.1106126665397$$
$$x_{20} = -14.1371669411541$$
$$x_{21} = 82$$
$$x_{22} = -60$$
$$x_{23} = 17.2787595947439$$
$$x_{24} = 34$$
$$x_{25} = -20.4203522483337$$
$$x_{26} = 42.4115008234622$$
$$x_{27} = -98$$
$$x_{28} = 69.4876649171307$$
$$x_{29} = -74$$
$$x_{30} = 84$$
$$x_{31} = 72$$
$$x_{32} = -76.9690200129499$$
$$x_{33} = 98.9601685880785$$
$$x_{34} = -45.553093477052$$
$$x_{35} = -62$$
$$x_{36} = 246.714684045448$$
$$x_{37} = 33.2157747709469$$
$$x_{38} = -24$$
$$x_{39} = -16$$
$$x_{40} = -42$$
$$x_{41} = 64$$
$$x_{42} = -87.75$$
$$x_{43} = -50$$
$$x_{44} = 28$$
$$x_{45} = -26.7035375555132$$
$$x_{46} = -1123.88490240028$$
$$x_{47} = -51.8362787842316$$
$$x_{48} = 4.71238898038469$$
$$x_{49} = -86$$
$$x_{50} = 61.261056745001$$
$$x_{51} = 54.9778714378214$$
$$x_{52} = 0.25$$
$$x_{53} = -68$$
$$x_{54} = -95.8185759344887$$
$$x_{55} = 96$$
$$x_{56} = -32.9867228626928$$
$$x_{57} = 23.5619449019235$$
$$x_{58} = 76$$
$$x_{59} = -43.4723442519539$$
$$x_{60} = -1.5707963267949$$
$$x_{61} = 92.6769832808989$$
$$x_{62} = 26$$
$$x_{63} = -70.6858347057703$$
$$x_{64} = 94.25$$
$$x_{65} = -48$$
$$x_{66} = 52$$
$$x_{67} = -18$$
$$x_{68} = -83.2522053201295$$
$$x_{69} = 86.3937979737193$$
$$x_{70} = -10$$
$$x_{71} = -66$$
$$x_{72} = 40$$
$$x_{73} = 88$$
$$x_{74} = -94$$
$$x_{75} = -12$$
$$x_{76} = -22$$
$$x_{77} = -30$$
$$x_{78} = 20$$
$$x_{79} = 14$$
$$x_{80} = 32$$
$$x_{81} = -64.4026493985908$$
$$x_{82} = 44$$
$$x_{83} = -86.9492424944954$$
$$x_{84} = -80$$
$$x_{85} = -54$$
$$x_{86} = 36.1283155162826$$
$$x_{87} = 73.8274273593601$$
$$x_{88} = -39.2699081698724$$
$$x_{89} = 58$$
$$x_{90} = -89.5353906273091$$
$$x_{91} = -92$$
$$x_{92} = 8$$
Signos de extremos en los puntos:
(90, 0)
(29.845130209103036, -2)
(-43.75, 0)
(78, 0)
(48.6946861306418, -2)
(-7.853981633974483, -2)
(10.995574287564276, -2)
(70, 0)
(-4, 0)
(-100, 0)
(-56, 0)
(67.54424205218055, -2)
(-6, 0)
(38, 0)
(-58.119464091411174, -2)
(46, 0)
(2, 0)
(-36, 0)
(80.11061266653972, -2)
(-14.137166941154069, -2)
(82, 0)
(-60, 0)
(17.278759594743864, -2)
(34, 0)
(-20.420352248333657, -2)
(42.411500823462205, -2)
(-98, 0)
(69.48766491713072, 0)
(-74, 0)
(84, 0)
(72, 0)
(-76.96902001294994, -2)
(98.96016858807849, -2)
(-45.553093477052, -2)
(-62, 0)
(246.7146840454484, 0)
(33.21577477094685, 0)
(-24, 0)
(-16, 0)
(-42, 0)
(64, 0)
(-87.75, 0)
(-50, 0)
(28, 0)
(-26.703537555513243, -2)
(-1123.8849024002832, 0)
(-51.83627878423159, -2)
(4.71238898038469, -2)
(-86, 0)
(61.26105674500097, -2)
(54.977871437821385, -2)
(0.25, 0)
(-68, 0)
(-95.81857593448869, -2)
(96, 0)
(-32.98672286269283, -2)
(23.56194490192345, -2)
(76, 0)
(-43.47234425195393, 0)
(-1.5707963267948966, -2)
(92.6769832808989, -2)
(26, 0)
(-70.68583470577035, -2)
(94.25, 0)
(-48, 0)
(52, 0)
(-18, 0)
(-83.25220532012952, -2)
(86.39379797371932, -2)
(-10, 0)
(-66, 0)
(40, 0)
(88, 0)
(-94, 0)
(-12, 0)
(-22, 0)
(-30, 0)
(20, 0)
(14, 0)
(32, 0)
(-64.40264939859077, -2)
(44, 0)
(-86.94924249449544, 0)
(-80, 0)
(-54, 0)
(36.12831551628262, -2)
(73.82742735936014, -2)
(-39.269908169872416, -2)
(58, 0)
(-89.53539062730911, -2)
(-92, 0)
(8, 0)
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:
$$x_{1} = 29.845130209103$$
$$x_{2} = 48.6946861306418$$
$$x_{3} = -7.85398163397448$$
$$x_{4} = 10.9955742875643$$
$$x_{5} = 67.5442420521806$$
$$x_{6} = -58.1194640914112$$
$$x_{7} = 80.1106126665397$$
$$x_{8} = -14.1371669411541$$
$$x_{9} = 17.2787595947439$$
$$x_{10} = -20.4203522483337$$
$$x_{11} = 42.4115008234622$$
$$x_{12} = -76.9690200129499$$
$$x_{13} = 98.9601685880785$$
$$x_{14} = -45.553093477052$$
$$x_{15} = -26.7035375555132$$
$$x_{16} = -51.8362787842316$$
$$x_{17} = 4.71238898038469$$
$$x_{18} = 61.261056745001$$
$$x_{19} = 54.9778714378214$$
$$x_{20} = -95.8185759344887$$
$$x_{21} = -32.9867228626928$$
$$x_{22} = 23.5619449019235$$
$$x_{23} = -1.5707963267949$$
$$x_{24} = 92.6769832808989$$
$$x_{25} = -70.6858347057703$$
$$x_{26} = -83.2522053201295$$
$$x_{27} = 86.3937979737193$$
$$x_{28} = -64.4026493985908$$
$$x_{29} = 36.1283155162826$$
$$x_{30} = 73.8274273593601$$
$$x_{31} = -39.2699081698724$$
$$x_{32} = -89.5353906273091$$
La función no tiene puntos máximos
Decrece en los intervalos
$$\left[98.9601685880785, \infty\right)$$
Crece en los intervalos
$$\left(-\infty, -95.8185759344887\right]$$