Найду корень уравнения: cos 3x=-1
x1 = -26.1799386626996
x2 = 42.9350997066251
x3 = 53.4070752151879
x4 = -38.7463098041192
x5 = 38.7463092377642
x6 = -17.8023583238223
x7 = 70.1622360266582
x8 = -53.4070752629576
x9 = 11.5191732261809
x10 = 74.3510260729228
x11 = 7.33038281101878
x12 = 51.3126798911883
x13 = 32.463123974206
x14 = -112.050138233058
x15 = -91.1061869787177
x16 = -89.0117914375586
x17 = 86.9173967892295
x18 = -15.7079632964021
x19 = -68.0678407687851
x20 = 95.294976948998
x21 = 63.8790507130208
x22 = -30.3687288181742
x23 = 17.8023584945614
x24 = 65.9734457527543
x25 = 36.6519141311518
x26 = 55.5014703723413
x27 = -65.973445765171
x28 = 26.1799388481654
x29 = -45.0294943910096
x30 = 34.5575190458158
x31 = -24.0855436072883
x32 = 80.6342112833208
x33 = 13.6135683335585
x34 = -19.8967529903279
x35 = -99.4837674953423
x36 = 59.6902605755492
x37 = 9.42477808135176
x38 = -11.5191731827034
x39 = 82.7286063849234
x40 = -70.1622358204673
x41 = -57.5958654038294
x42 = -78.5398161963125
x43 = 84.8230015250443
x44 = -95.2949773207426
x45 = -55.501470339224
x46 = 99.4837675171026
x47 = 21.9911485851801
x48 = -21.9911485864683
x49 = -36.6519142867263
x50 = -34.5575190560831
x51 = -7.33038302030457
x52 = 76.4454211314942
x53 = -9.42477810882172
x54 = -72.2566308884953
x55 = -49.2182850519149
x56 = -76.4454210695477
x57 = 93.2005824359632
x58 = -59.6902604573636
x59 = -80.6342113974683
x60 = 78.5398162009252
x61 = 30.3687289136091
x62 = 28.2743338652382
x63 = 40.8407043904405
x64 = -97.3893724165565
x65 = -61.7846554919628
x66 = 68.0678406256452
x67 = 15.7079634213668
x68 = -5.23598790794418
x69 = 97.3893723442985
x70 = -93.2005821937681
x71 = -13.6135682453022
x72 = -28.2743337333192
x73 = -1.04719735385243
x74 = -3.14159273948893
x75 = -51.3126801709688
x76 = -32.4631239211685
x77 = -74.3510259705245
x78 = 19.8967535532584
x79 = 61.7846556513336
x80 = 72.2566310277214
x81 = -47.1238898632468
x82 = -82.7286069074292
x83 = 57.595865484629