Se da la desigualdad:
$$\cos{\left(- t \right)} \leq -1$$
Para resolver esta desigualdad primero hay que resolver la ecuación correspondiente:
$$\cos{\left(- t \right)} = -1$$
Resolvemos:
$$x_{1} = -53.4070745786761$$
$$x_{2} = -47.1238901083229$$
$$x_{3} = 9.42477748794163$$
$$x_{4} = -65.9734461969855$$
$$x_{5} = -59.6902606928653$$
$$x_{6} = 15.7079634518075$$
$$x_{7} = 47.123889410773$$
$$x_{8} = 28.2743343711514$$
$$x_{9} = 3.1415922548952$$
$$x_{10} = 40.8407045848602$$
$$x_{11} = -72.2566311847166$$
$$x_{12} = 59.6902600526626$$
$$x_{13} = 21.9911485852059$$
$$x_{14} = 78.5398152766482$$
$$x_{15} = -9.4247781365785$$
$$x_{16} = -28.2743337069329$$
$$x_{17} = -34.5575188899093$$
$$x_{18} = -15.707962774825$$
$$x_{19} = 59.6902606104322$$
$$x_{20} = 34.5575197055812$$
$$x_{21} = -91.1061864815274$$
$$x_{22} = -21.9911485864417$$
$$x_{23} = 78.5398166181283$$
$$x_{24} = 91.1061865667532$$
$$x_{25} = -9.42477744529557$$
$$x_{26} = -53.4070745963886$$
$$x_{27} = 3.14159306054457$$
$$x_{28} = -65.9734453607004$$
$$x_{29} = 78.5398149750205$$
$$x_{30} = 91.1061873718352$$
$$x_{31} = 65.9734460390947$$
$$x_{32} = 97.3893717959212$$
$$x_{33} = 28.2743338651796$$
$$x_{34} = -34.5575196658297$$
$$x_{35} = -97.3893717476911$$
$$x_{36} = -40.8407049008781$$
$$x_{37} = -28.2743340989896$$
$$x_{38} = -15.7079635641079$$
$$x_{39} = 59.6902599104079$$
$$x_{40} = 72.2566315166773$$
$$x_{41} = -28.2743343914215$$
$$x_{42} = -9.42477752082051$$
$$x_{43} = 34.5575190219169$$
$$x_{44} = 21.9911480932338$$
$$x_{45} = -3.14159217367683$$
$$x_{46} = -21.9911490521325$$
$$x_{47} = 72.2566306985$$
$$x_{48} = 72.2566310277176$$
$$x_{49} = -59.6902599212271$$
$$x_{50} = 15.7079627593774$$
$$x_{51} = -15.7079632965989$$
$$x_{52} = 65.9734452390837$$
$$x_{53} = 40.8407042062167$$
$$x_{54} = -1127.83176318906$$
$$x_{55} = -84.8230020565447$$
$$x_{56} = 53.4070766553897$$
$$x_{57} = -84.8230012511693$$
$$x_{58} = -65.9734449870253$$
$$x_{59} = 53.4070746418597$$
$$x_{60} = 84.8230013636028$$
$$x_{61} = 47.1238902162437$$
$$x_{62} = 97.389372581711$$
$$x_{63} = -40.8407040952604$$
$$x_{64} = -91.106187265474$$
$$x_{65} = 84.8230021335997$$
$$x_{66} = -47.1238893275319$$
$$x_{67} = 78.5398168562347$$
$$x_{68} = 9.42477826738203$$
$$x_{69} = -53.407075294995$$
$$x_{70} = 15.7079629803241$$
$$x_{71} = 78.5398161804942$$
$$x_{72} = -97.3893724533348$$
$$x_{73} = 15.707963957033$$
$$x_{74} = -72.2566308657983$$
$$x_{75} = 40.8407045792514$$
$$x_{76} = -97.3893716284562$$
$$x_{77} = -78.5398160472843$$
$$x_{78} = 28.2743335663982$$
$$x_{79} = 21.9911489072506$$
$$x_{80} = 40.8407049800347$$
$$x_{81} = -78.5398168194507$$
$$x_{82} = 65.9734457529812$$
$$x_{83} = -21.991148226056$$
$$x_{84} = -72.2566315419804$$
$$x_{85} = -40.8407049290801$$
$$x_{86} = 34.5575195449229$$
$$x_{87} = -3.14159295109225$$
$$x_{88} = 53.407075424589$$
$$x_{89} = -59.6902604578012$$
$$x_{90} = -65.9734457649277$$
$$x_{1} = -53.4070745786761$$
$$x_{2} = -47.1238901083229$$
$$x_{3} = 9.42477748794163$$
$$x_{4} = -65.9734461969855$$
$$x_{5} = -59.6902606928653$$
$$x_{6} = 15.7079634518075$$
$$x_{7} = 47.123889410773$$
$$x_{8} = 28.2743343711514$$
$$x_{9} = 3.1415922548952$$
$$x_{10} = 40.8407045848602$$
$$x_{11} = -72.2566311847166$$
$$x_{12} = 59.6902600526626$$
$$x_{13} = 21.9911485852059$$
$$x_{14} = 78.5398152766482$$
$$x_{15} = -9.4247781365785$$
$$x_{16} = -28.2743337069329$$
$$x_{17} = -34.5575188899093$$
$$x_{18} = -15.707962774825$$
$$x_{19} = 59.6902606104322$$
$$x_{20} = 34.5575197055812$$
$$x_{21} = -91.1061864815274$$
$$x_{22} = -21.9911485864417$$
$$x_{23} = 78.5398166181283$$
$$x_{24} = 91.1061865667532$$
$$x_{25} = -9.42477744529557$$
$$x_{26} = -53.4070745963886$$
$$x_{27} = 3.14159306054457$$
$$x_{28} = -65.9734453607004$$
$$x_{29} = 78.5398149750205$$
$$x_{30} = 91.1061873718352$$
$$x_{31} = 65.9734460390947$$
$$x_{32} = 97.3893717959212$$
$$x_{33} = 28.2743338651796$$
$$x_{34} = -34.5575196658297$$
$$x_{35} = -97.3893717476911$$
$$x_{36} = -40.8407049008781$$
$$x_{37} = -28.2743340989896$$
$$x_{38} = -15.7079635641079$$
$$x_{39} = 59.6902599104079$$
$$x_{40} = 72.2566315166773$$
$$x_{41} = -28.2743343914215$$
$$x_{42} = -9.42477752082051$$
$$x_{43} = 34.5575190219169$$
$$x_{44} = 21.9911480932338$$
$$x_{45} = -3.14159217367683$$
$$x_{46} = -21.9911490521325$$
$$x_{47} = 72.2566306985$$
$$x_{48} = 72.2566310277176$$
$$x_{49} = -59.6902599212271$$
$$x_{50} = 15.7079627593774$$
$$x_{51} = -15.7079632965989$$
$$x_{52} = 65.9734452390837$$
$$x_{53} = 40.8407042062167$$
$$x_{54} = -1127.83176318906$$
$$x_{55} = -84.8230020565447$$
$$x_{56} = 53.4070766553897$$
$$x_{57} = -84.8230012511693$$
$$x_{58} = -65.9734449870253$$
$$x_{59} = 53.4070746418597$$
$$x_{60} = 84.8230013636028$$
$$x_{61} = 47.1238902162437$$
$$x_{62} = 97.389372581711$$
$$x_{63} = -40.8407040952604$$
$$x_{64} = -91.106187265474$$
$$x_{65} = 84.8230021335997$$
$$x_{66} = -47.1238893275319$$
$$x_{67} = 78.5398168562347$$
$$x_{68} = 9.42477826738203$$
$$x_{69} = -53.407075294995$$
$$x_{70} = 15.7079629803241$$
$$x_{71} = 78.5398161804942$$
$$x_{72} = -97.3893724533348$$
$$x_{73} = 15.707963957033$$
$$x_{74} = -72.2566308657983$$
$$x_{75} = 40.8407045792514$$
$$x_{76} = -97.3893716284562$$
$$x_{77} = -78.5398160472843$$
$$x_{78} = 28.2743335663982$$
$$x_{79} = 21.9911489072506$$
$$x_{80} = 40.8407049800347$$
$$x_{81} = -78.5398168194507$$
$$x_{82} = 65.9734457529812$$
$$x_{83} = -21.991148226056$$
$$x_{84} = -72.2566315419804$$
$$x_{85} = -40.8407049290801$$
$$x_{86} = 34.5575195449229$$
$$x_{87} = -3.14159295109225$$
$$x_{88} = 53.407075424589$$
$$x_{89} = -59.6902604578012$$
$$x_{90} = -65.9734457649277$$
Las raíces dadas
$$x_{54} = -1127.83176318906$$
$$x_{72} = -97.3893724533348$$
$$x_{35} = -97.3893717476911$$
$$x_{76} = -97.3893716284562$$
$$x_{64} = -91.106187265474$$
$$x_{21} = -91.1061864815274$$
$$x_{55} = -84.8230020565447$$
$$x_{57} = -84.8230012511693$$
$$x_{81} = -78.5398168194507$$
$$x_{77} = -78.5398160472843$$
$$x_{84} = -72.2566315419804$$
$$x_{11} = -72.2566311847166$$
$$x_{74} = -72.2566308657983$$
$$x_{4} = -65.9734461969855$$
$$x_{90} = -65.9734457649277$$
$$x_{28} = -65.9734453607004$$
$$x_{58} = -65.9734449870253$$
$$x_{5} = -59.6902606928653$$
$$x_{89} = -59.6902604578012$$
$$x_{49} = -59.6902599212271$$
$$x_{69} = -53.407075294995$$
$$x_{26} = -53.4070745963886$$
$$x_{1} = -53.4070745786761$$
$$x_{2} = -47.1238901083229$$
$$x_{66} = -47.1238893275319$$
$$x_{85} = -40.8407049290801$$
$$x_{36} = -40.8407049008781$$
$$x_{63} = -40.8407040952604$$
$$x_{34} = -34.5575196658297$$
$$x_{17} = -34.5575188899093$$
$$x_{41} = -28.2743343914215$$
$$x_{37} = -28.2743340989896$$
$$x_{16} = -28.2743337069329$$
$$x_{46} = -21.9911490521325$$
$$x_{22} = -21.9911485864417$$
$$x_{83} = -21.991148226056$$
$$x_{38} = -15.7079635641079$$
$$x_{51} = -15.7079632965989$$
$$x_{18} = -15.707962774825$$
$$x_{15} = -9.4247781365785$$
$$x_{42} = -9.42477752082051$$
$$x_{25} = -9.42477744529557$$
$$x_{87} = -3.14159295109225$$
$$x_{45} = -3.14159217367683$$
$$x_{9} = 3.1415922548952$$
$$x_{27} = 3.14159306054457$$
$$x_{3} = 9.42477748794163$$
$$x_{68} = 9.42477826738203$$
$$x_{50} = 15.7079627593774$$
$$x_{70} = 15.7079629803241$$
$$x_{6} = 15.7079634518075$$
$$x_{73} = 15.707963957033$$
$$x_{44} = 21.9911480932338$$
$$x_{13} = 21.9911485852059$$
$$x_{79} = 21.9911489072506$$
$$x_{78} = 28.2743335663982$$
$$x_{33} = 28.2743338651796$$
$$x_{8} = 28.2743343711514$$
$$x_{43} = 34.5575190219169$$
$$x_{86} = 34.5575195449229$$
$$x_{20} = 34.5575197055812$$
$$x_{53} = 40.8407042062167$$
$$x_{75} = 40.8407045792514$$
$$x_{10} = 40.8407045848602$$
$$x_{80} = 40.8407049800347$$
$$x_{7} = 47.123889410773$$
$$x_{61} = 47.1238902162437$$
$$x_{59} = 53.4070746418597$$
$$x_{88} = 53.407075424589$$
$$x_{56} = 53.4070766553897$$
$$x_{39} = 59.6902599104079$$
$$x_{12} = 59.6902600526626$$
$$x_{19} = 59.6902606104322$$
$$x_{52} = 65.9734452390837$$
$$x_{82} = 65.9734457529812$$
$$x_{31} = 65.9734460390947$$
$$x_{47} = 72.2566306985$$
$$x_{48} = 72.2566310277176$$
$$x_{40} = 72.2566315166773$$
$$x_{29} = 78.5398149750205$$
$$x_{14} = 78.5398152766482$$
$$x_{71} = 78.5398161804942$$
$$x_{23} = 78.5398166181283$$
$$x_{67} = 78.5398168562347$$
$$x_{60} = 84.8230013636028$$
$$x_{65} = 84.8230021335997$$
$$x_{24} = 91.1061865667532$$
$$x_{30} = 91.1061873718352$$
$$x_{32} = 97.3893717959212$$
$$x_{62} = 97.389372581711$$
son puntos de cambio del signo de desigualdad en las soluciones.
Primero definámonos con el signo hasta el punto extremo izquierdo:
$$x_{0} \leq x_{54}$$
Consideremos, por ejemplo, el punto
$$x_{0} = x_{54} - \frac{1}{10}$$
=
$$-1127.83176318906 + - \frac{1}{10}$$
=
$$-1127.93176318906$$
lo sustituimos en la expresión
$$\cos{\left(- t \right)} \leq -1$$
$$\cos{\left(- t \right)} \leq -1$$
cos(t) <= -1
Entonces
$$x \leq -1127.83176318906$$
no se cumple
significa que una de las soluciones de nuestra ecuación será con:
$$x \geq -1127.83176318906 \wedge x \leq -97.3893724533348$$
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x54 x72 x35 x76 x64 x21 x55 x57 x81 x77 x84 x11 x74 x4 x90 x28 x58 x5 x89 x49 x69 x26 x1 x2 x66 x85 x36 x63 x34 x17 x41 x37 x16 x46 x22 x83 x38 x51 x18 x15 x42 x25 x87 x45 x9 x27 x3 x68 x50 x70 x6 x73 x44 x13 x79 x78 x33 x8 x43 x86 x20 x53 x75 x10 x80 x7 x61 x59 x88 x56 x39 x12 x19 x52 x82 x31 x47 x48 x40 x29 x14 x71 x23 x67 x60 x65 x24 x30 x32 x62
Recibiremos otras soluciones de la desigualdad pasando al polo siguiente etc.
etc.
Respuesta:
$$x \geq -1127.83176318906 \wedge x \leq -97.3893724533348$$
$$x \geq -97.3893717476911 \wedge x \leq -97.3893716284562$$
$$x \geq -91.106187265474 \wedge x \leq -91.1061864815274$$
$$x \geq -84.8230020565447 \wedge x \leq -84.8230012511693$$
$$x \geq -78.5398168194507 \wedge x \leq -78.5398160472843$$
$$x \geq -72.2566315419804 \wedge x \leq -72.2566311847166$$
$$x \geq -72.2566308657983 \wedge x \leq -65.9734461969855$$
$$x \geq -65.9734457649277 \wedge x \leq -65.9734453607004$$
$$x \geq -65.9734449870253 \wedge x \leq -59.6902606928653$$
$$x \geq -59.6902604578012 \wedge x \leq -59.6902599212271$$
$$x \geq -53.407075294995 \wedge x \leq -53.4070745963886$$
$$x \geq -53.4070745786761 \wedge x \leq -47.1238901083229$$
$$x \geq -47.1238893275319 \wedge x \leq -40.8407049290801$$
$$x \geq -40.8407049008781 \wedge x \leq -40.8407040952604$$
$$x \geq -34.5575196658297 \wedge x \leq -34.5575188899093$$
$$x \geq -28.2743343914215 \wedge x \leq -28.2743340989896$$
$$x \geq -28.2743337069329 \wedge x \leq -21.9911490521325$$
$$x \geq -21.9911485864417 \wedge x \leq -21.991148226056$$
$$x \geq -15.7079635641079 \wedge x \leq -15.7079632965989$$
$$x \geq -15.707962774825 \wedge x \leq -9.4247781365785$$
$$x \geq -9.42477752082051 \wedge x \leq -9.42477744529557$$
$$x \geq -3.14159295109225 \wedge x \leq -3.14159217367683$$
$$x \geq 3.1415922548952 \wedge x \leq 3.14159306054457$$
$$x \geq 9.42477748794163 \wedge x \leq 9.42477826738203$$
$$x \geq 15.7079627593774 \wedge x \leq 15.7079629803241$$
$$x \geq 15.7079634518075 \wedge x \leq 15.707963957033$$
$$x \geq 21.9911480932338 \wedge x \leq 21.9911485852059$$
$$x \geq 21.9911489072506 \wedge x \leq 28.2743335663982$$
$$x \geq 28.2743338651796 \wedge x \leq 28.2743343711514$$
$$x \geq 34.5575190219169 \wedge x \leq 34.5575195449229$$
$$x \geq 34.5575197055812 \wedge x \leq 40.8407042062167$$
$$x \geq 40.8407045792514 \wedge x \leq 40.8407045848602$$
$$x \geq 40.8407049800347 \wedge x \leq 47.123889410773$$
$$x \geq 47.1238902162437 \wedge x \leq 53.4070746418597$$
$$x \geq 53.407075424589 \wedge x \leq 53.4070766553897$$
$$x \geq 59.6902599104079 \wedge x \leq 59.6902600526626$$
$$x \geq 59.6902606104322 \wedge x \leq 65.9734452390837$$
$$x \geq 65.9734457529812 \wedge x \leq 65.9734460390947$$
$$x \geq 72.2566306985 \wedge x \leq 72.2566310277176$$
$$x \geq 72.2566315166773 \wedge x \leq 78.5398149750205$$
$$x \geq 78.5398152766482 \wedge x \leq 78.5398161804942$$
$$x \geq 78.5398166181283 \wedge x \leq 78.5398168562347$$
$$x \geq 84.8230013636028 \wedge x \leq 84.8230021335997$$
$$x \geq 91.1061865667532 \wedge x \leq 91.1061873718352$$
$$x \geq 97.3893717959212 \wedge x \leq 97.389372581711$$