Найду корень уравнения: cos(x)=4/7
x1 = -acos(4/7) + 2*pi
x2 = acos(4/7)
x1 = 93.2852288598091
x2 = 74.4356729382704
x3 = -5.3206345592949
x4 = 36.7365610951928
x5 = -63.7944038196806
x6 = 17.8870051736541
x7 = -0.962550747884687
x8 = -101.493515662758
x9 = -68.1524876310908
x10 = 63.7944038196806
x11 = 19.8121066694234
x12 = -70.0775891268601
x13 = 76.3607744340397
x14 = -13.5289213622439
x15 = -44.9448478981418
x16 = 43.0197464023724
x17 = 13.5289213622439
x18 = -49.302931709552
x19 = -38.6616625909622
x20 = -87.0020435526295
x21 = 30.4533757880132
x22 = 82.6439597412193
x23 = -93.2852288598091
x24 = -19.8121066694234
x25 = 44.9448478981418
x26 = 26.095291976603
x27 = 49.302931709552
x28 = -80.7188582454499
x29 = -26.095291976603
x30 = -99.5684141669887
x31 = 61.8693023239112
x32 = 5.3206345592949
x33 = -74.4356729382704
x34 = 57.511218512501
x35 = 55.5861170167316
x36 = 32.3784772837826
x37 = -17.8870051736541
x38 = -32.3784772837826
x39 = 87.0020435526295
x40 = -76.3607744340397
x41 = 88.9271450483989
x42 = -51.2280332053214
x43 = -30.4533757880132
x44 = -95.2103303555785
x45 = -24.1701904808337
x46 = 68.1524876310908
x47 = 80.7188582454499
x48 = -11.6038198664745
x49 = 24.1701904808337
x50 = 95.2103303555785
x51 = 38.6616625909622
x52 = -36.7365610951928
x53 = 11.6038198664745
x54 = 51.2280332053214
x55 = 70.0775891268601
x56 = -88.9271450483989
x57 = 7.24573605506427
x58 = -55.5861170167316
x59 = -61.8693023239112
x60 = -7.24573605506427
x61 = -57.511218512501
x62 = -82.6439597412193
x63 = 0.962550747884687
x64 = -43.0197464023724
x65 = 99.5684141669887