Abs(cos(x))>0 (неравенство)

Учитель очень удивится увидев твоё верное решение 😼

В неравенстве неизвестная

    Укажите решение неравенства: Abs(cos(x))>0 (множество решений неравенства)

    Решение

    Вы ввели [src]
    |cos(x)| > 0
    cos(x)>0\left|{\cos{\left (x \right )}}\right| > 0
    Подробное решение
    Дано неравенство:
    cos(x)>0\left|{\cos{\left (x \right )}}\right| > 0
    Чтобы решить это нер-во - надо сначала решить соотвествующее ур-ние:
    cos(x)=0\left|{\cos{\left (x \right )}}\right| = 0
    Решаем:
    x1=54.9778714378x_{1} = -54.9778714378
    x2=39.2699081699x_{2} = 39.2699081699
    x3=51.8362787842x_{3} = 51.8362787842
    x4=86.3937979737x_{4} = 86.3937979737
    x5=17.2787595947x_{5} = -17.2787595947
    x6=45.5530934771x_{6} = 45.5530934771
    x7=61.261056745x_{7} = 61.261056745
    x8=83.2522053201x_{8} = 83.2522053201
    x9=70.6858347058x_{9} = -70.6858347058
    x10=89.5353906273x_{10} = -89.5353906273
    x11=92.6769832809x_{11} = 92.6769832809
    x12=76.9690200129x_{12} = 76.9690200129
    x13=32.9867228627x_{13} = -32.9867228627
    x14=17.2787595947x_{14} = 17.2787595947
    x15=48.6946861306x_{15} = -48.6946861306
    x16=80.1106126665x_{16} = -80.1106126665
    x17=42.4115008235x_{17} = -42.4115008235
    x18=58.1194640914x_{18} = -58.1194640914
    x19=1.57079632679x_{19} = 1.57079632679
    x20=95.8185759345x_{20} = -95.8185759345
    x21=95.8185759345x_{21} = 95.8185759345
    x22=36.1283155163x_{22} = -36.1283155163
    x23=64.4026493986x_{23} = -64.4026493986
    x24=61.261056745x_{24} = -61.261056745
    x25=92.6769832809x_{25} = -92.6769832809
    x26=32.9867228627x_{26} = 32.9867228627
    x27=14.1371669412x_{27} = -14.1371669412
    x28=80.1106126665x_{28} = 80.1106126665
    x29=4.71238898038x_{29} = 4.71238898038
    x30=10.9955742876x_{30} = 10.9955742876
    x31=7.85398163397x_{31} = 7.85398163397
    x32=23.5619449019x_{32} = 23.5619449019
    x33=39.2699081699x_{33} = -39.2699081699
    x34=64.4026493986x_{34} = 64.4026493986
    x35=73.8274273594x_{35} = -73.8274273594
    x36=14.1371669412x_{36} = 14.1371669412
    x37=26.7035375555x_{37} = -26.7035375555
    x38=83.2522053201x_{38} = -83.2522053201
    x39=98.9601685881x_{39} = -98.9601685881
    x40=48.6946861306x_{40} = 48.6946861306
    x41=98.9601685881x_{41} = 98.9601685881
    x42=45.5530934771x_{42} = -45.5530934771
    x43=51.8362787842x_{43} = -51.8362787842
    x44=67.5442420522x_{44} = -67.5442420522
    x45=54.9778714378x_{45} = 54.9778714378
    x46=26.7035375555x_{46} = 26.7035375555
    x47=86.3937979737x_{47} = -86.3937979737
    x48=20.4203522483x_{48} = -20.4203522483
    x49=7.85398163397x_{49} = -7.85398163397
    x50=4.71238898038x_{50} = -4.71238898038
    x51=76.9690200129x_{51} = -76.9690200129
    x52=89.5353906273x_{52} = 89.5353906273
    x53=10.9955742876x_{53} = -10.9955742876
    x54=1.57079632679x_{54} = -1.57079632679
    x55=23.5619449019x_{55} = -23.5619449019
    x56=73.8274273594x_{56} = 73.8274273594
    x57=70.6858347058x_{57} = 70.6858347058
    x58=29.8451302091x_{58} = 29.8451302091
    x59=42.4115008235x_{59} = 42.4115008235
    x60=67.5442420522x_{60} = 67.5442420522
    x61=20.4203522483x_{61} = 20.4203522483
    x62=29.8451302091x_{62} = -29.8451302091
    x1=54.9778714378x_{1} = -54.9778714378
    x2=39.2699081699x_{2} = 39.2699081699
    x3=51.8362787842x_{3} = 51.8362787842
    x4=86.3937979737x_{4} = 86.3937979737
    x5=17.2787595947x_{5} = -17.2787595947
    x6=45.5530934771x_{6} = 45.5530934771
    x7=61.261056745x_{7} = 61.261056745
    x8=83.2522053201x_{8} = 83.2522053201
    x9=70.6858347058x_{9} = -70.6858347058
    x10=89.5353906273x_{10} = -89.5353906273
    x11=92.6769832809x_{11} = 92.6769832809
    x12=76.9690200129x_{12} = 76.9690200129
    x13=32.9867228627x_{13} = -32.9867228627
    x14=17.2787595947x_{14} = 17.2787595947
    x15=48.6946861306x_{15} = -48.6946861306
    x16=80.1106126665x_{16} = -80.1106126665
    x17=42.4115008235x_{17} = -42.4115008235
    x18=58.1194640914x_{18} = -58.1194640914
    x19=1.57079632679x_{19} = 1.57079632679
    x20=95.8185759345x_{20} = -95.8185759345
    x21=95.8185759345x_{21} = 95.8185759345
    x22=36.1283155163x_{22} = -36.1283155163
    x23=64.4026493986x_{23} = -64.4026493986
    x24=61.261056745x_{24} = -61.261056745
    x25=92.6769832809x_{25} = -92.6769832809
    x26=32.9867228627x_{26} = 32.9867228627
    x27=14.1371669412x_{27} = -14.1371669412
    x28=80.1106126665x_{28} = 80.1106126665
    x29=4.71238898038x_{29} = 4.71238898038
    x30=10.9955742876x_{30} = 10.9955742876
    x31=7.85398163397x_{31} = 7.85398163397
    x32=23.5619449019x_{32} = 23.5619449019
    x33=39.2699081699x_{33} = -39.2699081699
    x34=64.4026493986x_{34} = 64.4026493986
    x35=73.8274273594x_{35} = -73.8274273594
    x36=14.1371669412x_{36} = 14.1371669412
    x37=26.7035375555x_{37} = -26.7035375555
    x38=83.2522053201x_{38} = -83.2522053201
    x39=98.9601685881x_{39} = -98.9601685881
    x40=48.6946861306x_{40} = 48.6946861306
    x41=98.9601685881x_{41} = 98.9601685881
    x42=45.5530934771x_{42} = -45.5530934771
    x43=51.8362787842x_{43} = -51.8362787842
    x44=67.5442420522x_{44} = -67.5442420522
    x45=54.9778714378x_{45} = 54.9778714378
    x46=26.7035375555x_{46} = 26.7035375555
    x47=86.3937979737x_{47} = -86.3937979737
    x48=20.4203522483x_{48} = -20.4203522483
    x49=7.85398163397x_{49} = -7.85398163397
    x50=4.71238898038x_{50} = -4.71238898038
    x51=76.9690200129x_{51} = -76.9690200129
    x52=89.5353906273x_{52} = 89.5353906273
    x53=10.9955742876x_{53} = -10.9955742876
    x54=1.57079632679x_{54} = -1.57079632679
    x55=23.5619449019x_{55} = -23.5619449019
    x56=73.8274273594x_{56} = 73.8274273594
    x57=70.6858347058x_{57} = 70.6858347058
    x58=29.8451302091x_{58} = 29.8451302091
    x59=42.4115008235x_{59} = 42.4115008235
    x60=67.5442420522x_{60} = 67.5442420522
    x61=20.4203522483x_{61} = 20.4203522483
    x62=29.8451302091x_{62} = -29.8451302091
    Данные корни
    x39=98.9601685881x_{39} = -98.9601685881
    x20=95.8185759345x_{20} = -95.8185759345
    x25=92.6769832809x_{25} = -92.6769832809
    x10=89.5353906273x_{10} = -89.5353906273
    x47=86.3937979737x_{47} = -86.3937979737
    x38=83.2522053201x_{38} = -83.2522053201
    x16=80.1106126665x_{16} = -80.1106126665
    x51=76.9690200129x_{51} = -76.9690200129
    x35=73.8274273594x_{35} = -73.8274273594
    x9=70.6858347058x_{9} = -70.6858347058
    x44=67.5442420522x_{44} = -67.5442420522
    x23=64.4026493986x_{23} = -64.4026493986
    x24=61.261056745x_{24} = -61.261056745
    x18=58.1194640914x_{18} = -58.1194640914
    x1=54.9778714378x_{1} = -54.9778714378
    x43=51.8362787842x_{43} = -51.8362787842
    x15=48.6946861306x_{15} = -48.6946861306
    x42=45.5530934771x_{42} = -45.5530934771
    x17=42.4115008235x_{17} = -42.4115008235
    x33=39.2699081699x_{33} = -39.2699081699
    x22=36.1283155163x_{22} = -36.1283155163
    x13=32.9867228627x_{13} = -32.9867228627
    x62=29.8451302091x_{62} = -29.8451302091
    x37=26.7035375555x_{37} = -26.7035375555
    x55=23.5619449019x_{55} = -23.5619449019
    x48=20.4203522483x_{48} = -20.4203522483
    x5=17.2787595947x_{5} = -17.2787595947
    x27=14.1371669412x_{27} = -14.1371669412
    x53=10.9955742876x_{53} = -10.9955742876
    x49=7.85398163397x_{49} = -7.85398163397
    x50=4.71238898038x_{50} = -4.71238898038
    x54=1.57079632679x_{54} = -1.57079632679
    x19=1.57079632679x_{19} = 1.57079632679
    x29=4.71238898038x_{29} = 4.71238898038
    x31=7.85398163397x_{31} = 7.85398163397
    x30=10.9955742876x_{30} = 10.9955742876
    x36=14.1371669412x_{36} = 14.1371669412
    x14=17.2787595947x_{14} = 17.2787595947
    x61=20.4203522483x_{61} = 20.4203522483
    x32=23.5619449019x_{32} = 23.5619449019
    x46=26.7035375555x_{46} = 26.7035375555
    x58=29.8451302091x_{58} = 29.8451302091
    x26=32.9867228627x_{26} = 32.9867228627
    x2=39.2699081699x_{2} = 39.2699081699
    x59=42.4115008235x_{59} = 42.4115008235
    x6=45.5530934771x_{6} = 45.5530934771
    x40=48.6946861306x_{40} = 48.6946861306
    x3=51.8362787842x_{3} = 51.8362787842
    x45=54.9778714378x_{45} = 54.9778714378
    x7=61.261056745x_{7} = 61.261056745
    x34=64.4026493986x_{34} = 64.4026493986
    x60=67.5442420522x_{60} = 67.5442420522
    x57=70.6858347058x_{57} = 70.6858347058
    x56=73.8274273594x_{56} = 73.8274273594
    x12=76.9690200129x_{12} = 76.9690200129
    x28=80.1106126665x_{28} = 80.1106126665
    x8=83.2522053201x_{8} = 83.2522053201
    x4=86.3937979737x_{4} = 86.3937979737
    x52=89.5353906273x_{52} = 89.5353906273
    x11=92.6769832809x_{11} = 92.6769832809
    x21=95.8185759345x_{21} = 95.8185759345
    x41=98.9601685881x_{41} = 98.9601685881
    являются точками смены знака неравенства в решениях.
    Сначала определимся со знаком до крайней левой точки:
    x0<x39x_{0} < x_{39}
    Возьмём например точку
    x0=x39110x_{0} = x_{39} - \frac{1}{10}
    =
    99.0601685881-99.0601685881
    =
    99.0601685881-99.0601685881
    подставляем в выражение
    cos(x)>0\left|{\cos{\left (x \right )}}\right| > 0
    cos(99.0601685881)>0\left|{\cos{\left (-99.0601685881 \right )}}\right| > 0
    0.0998334166682317 > 0

    значит одно из решений нашего неравенства будет при:
    x<98.9601685881x < -98.9601685881
     _____           _____           _____           _____           _____           _____           _____           _____           _____           _____           _____           _____           _____           _____           _____           _____           _____           _____           _____           _____           _____           _____           _____           _____           _____           _____           _____           _____           _____           _____           _____           _____          
          \         /     \         /     \         /     \         /     \         /     \         /     \         /     \         /     \         /     \         /     \         /     \         /     \         /     \         /     \         /     \         /     \         /     \         /     \         /     \         /     \         /     \         /     \         /     \         /     \         /     \         /     \         /     \         /     \         /     \         /     \         /
    -------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------
           x39      x20      x25      x10      x47      x38      x16      x51      x35      x9      x44      x23      x24      x18      x1      x43      x15      x42      x17      x33      x22      x13      x62      x37      x55      x48      x5      x27      x53      x49      x50      x54      x19      x29      x31      x30      x36      x14      x61      x32      x46      x58      x26      x2      x59      x6      x40      x3      x45      x7      x34      x60      x57      x56      x12      x28      x8      x4      x52      x11      x21      x41

    Другие решения неравенства будем получать переходом на следующий полюс
    и т.д.
    Ответ:
    x<98.9601685881x < -98.9601685881
    x>95.8185759345x<92.6769832809x > -95.8185759345 \wedge x < -92.6769832809
    x>89.5353906273x<86.3937979737x > -89.5353906273 \wedge x < -86.3937979737
    x>83.2522053201x<80.1106126665x > -83.2522053201 \wedge x < -80.1106126665
    x>76.9690200129x<73.8274273594x > -76.9690200129 \wedge x < -73.8274273594
    x>70.6858347058x<67.5442420522x > -70.6858347058 \wedge x < -67.5442420522
    x>64.4026493986x<61.261056745x > -64.4026493986 \wedge x < -61.261056745
    x>58.1194640914x<54.9778714378x > -58.1194640914 \wedge x < -54.9778714378
    x>51.8362787842x<48.6946861306x > -51.8362787842 \wedge x < -48.6946861306
    x>45.5530934771x<42.4115008235x > -45.5530934771 \wedge x < -42.4115008235
    x>39.2699081699x<36.1283155163x > -39.2699081699 \wedge x < -36.1283155163
    x>32.9867228627x<29.8451302091x > -32.9867228627 \wedge x < -29.8451302091
    x>26.7035375555x<23.5619449019x > -26.7035375555 \wedge x < -23.5619449019
    x>20.4203522483x<17.2787595947x > -20.4203522483 \wedge x < -17.2787595947
    x>14.1371669412x<10.9955742876x > -14.1371669412 \wedge x < -10.9955742876
    x>7.85398163397x<4.71238898038x > -7.85398163397 \wedge x < -4.71238898038
    x>1.57079632679x<1.57079632679x > -1.57079632679 \wedge x < 1.57079632679
    x>4.71238898038x<7.85398163397x > 4.71238898038 \wedge x < 7.85398163397
    x>10.9955742876x<14.1371669412x > 10.9955742876 \wedge x < 14.1371669412
    x>17.2787595947x<20.4203522483x > 17.2787595947 \wedge x < 20.4203522483
    x>23.5619449019x<26.7035375555x > 23.5619449019 \wedge x < 26.7035375555
    x>29.8451302091x<32.9867228627x > 29.8451302091 \wedge x < 32.9867228627
    x>39.2699081699x<42.4115008235x > 39.2699081699 \wedge x < 42.4115008235
    x>45.5530934771x<48.6946861306x > 45.5530934771 \wedge x < 48.6946861306
    x>51.8362787842x<54.9778714378x > 51.8362787842 \wedge x < 54.9778714378
    x>61.261056745x<64.4026493986x > 61.261056745 \wedge x < 64.4026493986
    x>67.5442420522x<70.6858347058x > 67.5442420522 \wedge x < 70.6858347058
    x>73.8274273594x<76.9690200129x > 73.8274273594 \wedge x < 76.9690200129
    x>80.1106126665x<83.2522053201x > 80.1106126665 \wedge x < 83.2522053201
    x>86.3937979737x<89.5353906273x > 86.3937979737 \wedge x < 89.5353906273
    x>92.6769832809x<95.8185759345x > 92.6769832809 \wedge x < 95.8185759345
    x>98.9601685881x > 98.9601685881
    Решение неравенства на графике
    02468-8-6-4-2-101002
    Быстрый ответ [src]
      /   /             pi\     /pi          3*pi\     /3*pi            \\
    Or|And|-oo < x, x < --|, And|-- < x, x < ----|, And|---- < x, x < oo||
      \   \             2 /     \2            2  /     \ 2              //
    (<xx<π2)(π2<xx<3π2)(3π2<xx<)\left(-\infty < x \wedge x < \frac{\pi}{2}\right) \vee \left(\frac{\pi}{2} < x \wedge x < \frac{3 \pi}{2}\right) \vee \left(\frac{3 \pi}{2} < x \wedge x < \infty\right)
    Быстрый ответ 2 [src]
          pi     pi  3*pi     3*pi     
    (-oo, --) U (--, ----) U (----, oo)
          2      2    2        2       
    x(,π2)(π2,3π2)(3π2,)x \in \left(-\infty, \frac{\pi}{2}\right) \cup \left(\frac{\pi}{2}, \frac{3 \pi}{2}\right) \cup \left(\frac{3 \pi}{2}, \infty\right)