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$$- \frac{\left(x + \sin{\left(2 x \right)}\right) \cos{\left(x \right)}}{\sin^{2}{\left(x \right)}} + \frac{2 \cos{\left(2 x \right)} + 1}{\sin{\left(x \right)}} = 0$$
Resolvermos esta ecuaciónRaíces de esta ecuación
$$x_{1} = 61.2773658575433$$
$$x_{2} = -20.4689380267502$$
$$x_{3} = -39.2953181686786$$
$$x_{4} = 23.604134582198$$
$$x_{5} = 33.0169458205959$$
$$x_{6} = -83.2642112429691$$
$$x_{7} = -76.9820049516737$$
$$x_{8} = 20.4689380267502$$
$$x_{9} = 36.1559243301836$$
$$x_{10} = -64.4181642526582$$
$$x_{11} = -70.6999723871001$$
$$x_{12} = 4.90003208410804$$
$$x_{13} = -42.4350358095921$$
$$x_{14} = 67.5590363627001$$
$$x_{15} = 92.6877692623911$$
$$x_{16} = 29.8785121081536$$
$$x_{17} = -45.575010738978$$
$$x_{18} = 76.9820049516737$$
$$x_{19} = 89.5465547553057$$
$$x_{20} = -36.1559243301836$$
$$x_{21} = 64.4181642526582$$
$$x_{22} = 70.6999723871001$$
$$x_{23} = -14.2067626065023$$
$$x_{24} = -92.6877692623911$$
$$x_{25} = -89.5465547553057$$
$$x_{26} = -7.97511398695608$$
$$x_{27} = -58.1366530875265$$
$$x_{28} = -86.4053677142634$$
$$x_{29} = -61.2773658575433$$
$$x_{30} = -67.5590363627001$$
$$x_{31} = -26.7408124348997$$
$$x_{32} = -1.93718340864326$$
$$x_{33} = 17.3360027927035$$
$$x_{34} = 58.1366530875265$$
$$x_{35} = 54.9960405616261$$
$$x_{36} = 98.9702702267906$$
$$x_{37} = -80.1230889308106$$
$$x_{38} = -95.8290085380668$$
$$x_{39} = 45.575010738978$$
$$x_{40} = -73.8409641878896$$
$$x_{41} = 73.8409641878896$$
$$x_{42} = 95.8290085380668$$
$$x_{43} = 7.97511398695608$$
$$x_{44} = -33.0169458205959$$
$$x_{45} = 39.2953181686786$$
$$x_{46} = 48.7151934688099$$
$$x_{47} = 14.2067626065023$$
$$x_{48} = -54.9960405616261$$
$$x_{49} = 26.7408124348997$$
$$x_{50} = 86.4053677142634$$
$$x_{51} = -51.8555464232494$$
$$x_{52} = 51.8555464232494$$
$$x_{53} = -17.3360027927035$$
$$x_{54} = 83.2642112429691$$
$$x_{55} = -29.8785121081536$$
$$x_{56} = -23.604134582198$$
$$x_{57} = -48.7151934688099$$
$$x_{58} = 11.0841489258958$$
$$x_{59} = 1.93718340864326$$
$$x_{60} = 80.1230889308106$$
$$x_{61} = -98.9702702267906$$
$$x_{62} = -4.90003208410804$$
$$x_{63} = -11.0841489258958$$
$$x_{64} = 42.4350358095921$$
Signos de extremos en los puntos:
(61.27736585754328, -61.2528994777449)
(-20.468938026750187, 20.3959877418391)
(-39.2953181686786, 39.2571929189699)
(23.60413458219802, -23.5408031583217)
(33.016945820595865, 32.9715941356851)
(-83.26421124296907, 83.246201277169)
(-76.98200495167366, 76.9625261753177)
(20.468938026750187, 20.3959877418391)
(36.15592433018363, -36.1144979601887)
(-64.41816425265819, 64.3948896376509)
(-70.6999723871001, 70.6787640991425)
(4.900032084108042, -4.61449316680033)
(-42.435035809592144, -42.3997251846591)
(67.55903636270008, -67.5368428733049)
(92.68776926239111, -92.6715895059293)
(29.878512108153572, -29.8284160199475)
(-45.57501073897802, 45.5421282670928)
(76.98200495167366, 76.9625261753177)
(89.54655475530569, 89.5298076936821)
(-36.15592433018363, -36.1144979601887)
(64.41816425265819, 64.3948896376509)
(70.6999723871001, 70.6787640991425)
(-14.206762606502263, 14.1021588144674)
(-92.68776926239111, -92.6715895059293)
(-89.54655475530569, 89.5298076936821)
(-7.975113986956083, 7.79231077920284)
(-58.1366530875265, 58.1108664195298)
(-86.40536771426336, -86.3880121355511)
(-61.27736585754328, -61.2528994777449)
(-67.55903636270008, -67.5368428733049)
(-26.7408124348997, 26.6848677639468)
(-1.9371834086432644, 1.35840983054794)
(17.336002792703507, -17.2500209082052)
(58.1366530875265, 58.1108664195298)
(54.996040561626074, -54.9687831276782)
(98.97027022679063, -98.9551171244958)
(-80.12308893081064, -80.1043733207136)
(-95.82900853806676, 95.8133589230563)
(45.57501073897802, 45.5421282670928)
(-73.84096418788961, -73.8206573948496)
(73.84096418788961, -73.8206573948496)
(95.82900853806676, 95.8133589230563)
(7.975113986956083, 7.79231077920284)
(-33.016945820595865, 32.9715941356851)
(39.2953181686786, 39.2571929189699)
(48.715193468809915, -48.6844270721817)
(14.206762606502263, 14.1021588144674)
(-54.996040561626074, -54.9687831276782)
(26.7408124348997, 26.6848677639468)
(86.40536771426336, -86.3880121355511)
(-51.85554642324937, 51.8266404947564)
(51.85554642324937, 51.8266404947564)
(-17.336002792703507, -17.2500209082052)
(83.26421124296907, 83.246201277169)
(-29.878512108153572, -29.8284160199475)
(-23.60413458219802, -23.5408031583217)
(-48.715193468809915, -48.6844270721817)
(11.08414892589577, -10.9508539438365)
(1.9371834086432644, 1.35840983054794)
(80.12308893081064, -80.1043733207136)
(-98.97027022679063, -98.9551171244958)
(-4.900032084108042, -4.61449316680033)
(-11.08414892589577, -10.9508539438365)
(42.435035809592144, -42.3997251846591)
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:
$$x_{1} = -20.4689380267502$$
$$x_{2} = -39.2953181686786$$
$$x_{3} = 33.0169458205959$$
$$x_{4} = -83.2642112429691$$
$$x_{5} = -76.9820049516737$$
$$x_{6} = 20.4689380267502$$
$$x_{7} = -64.4181642526582$$
$$x_{8} = -70.6999723871001$$
$$x_{9} = -45.575010738978$$
$$x_{10} = 76.9820049516737$$
$$x_{11} = 89.5465547553057$$
$$x_{12} = 64.4181642526582$$
$$x_{13} = 70.6999723871001$$
$$x_{14} = -14.2067626065023$$
$$x_{15} = -89.5465547553057$$
$$x_{16} = -7.97511398695608$$
$$x_{17} = -58.1366530875265$$
$$x_{18} = -26.7408124348997$$
$$x_{19} = -1.93718340864326$$
$$x_{20} = 58.1366530875265$$
$$x_{21} = -95.8290085380668$$
$$x_{22} = 45.575010738978$$
$$x_{23} = 95.8290085380668$$
$$x_{24} = 7.97511398695608$$
$$x_{25} = -33.0169458205959$$
$$x_{26} = 39.2953181686786$$
$$x_{27} = 14.2067626065023$$
$$x_{28} = 26.7408124348997$$
$$x_{29} = -51.8555464232494$$
$$x_{30} = 51.8555464232494$$
$$x_{31} = 83.2642112429691$$
$$x_{32} = 1.93718340864326$$
Puntos máximos de la función:
$$x_{32} = 61.2773658575433$$
$$x_{32} = 23.604134582198$$
$$x_{32} = 36.1559243301836$$
$$x_{32} = 4.90003208410804$$
$$x_{32} = -42.4350358095921$$
$$x_{32} = 67.5590363627001$$
$$x_{32} = 92.6877692623911$$
$$x_{32} = 29.8785121081536$$
$$x_{32} = -36.1559243301836$$
$$x_{32} = -92.6877692623911$$
$$x_{32} = -86.4053677142634$$
$$x_{32} = -61.2773658575433$$
$$x_{32} = -67.5590363627001$$
$$x_{32} = 17.3360027927035$$
$$x_{32} = 54.9960405616261$$
$$x_{32} = 98.9702702267906$$
$$x_{32} = -80.1230889308106$$
$$x_{32} = -73.8409641878896$$
$$x_{32} = 73.8409641878896$$
$$x_{32} = 48.7151934688099$$
$$x_{32} = -54.9960405616261$$
$$x_{32} = 86.4053677142634$$
$$x_{32} = -17.3360027927035$$
$$x_{32} = -29.8785121081536$$
$$x_{32} = -23.604134582198$$
$$x_{32} = -48.7151934688099$$
$$x_{32} = 11.0841489258958$$
$$x_{32} = 80.1230889308106$$
$$x_{32} = -98.9702702267906$$
$$x_{32} = -4.90003208410804$$
$$x_{32} = -11.0841489258958$$
$$x_{32} = 42.4350358095921$$
Decrece en los intervalos
$$\left[95.8290085380668, \infty\right)$$
Crece en los intervalos
$$\left(-\infty, -95.8290085380668\right]$$