Найду корень уравнения: cos(a)=-(8/15)
a1 = -acos(-8/15) + 2*pi
a2 = acos(-8/15)
a1 = -29.2825939645592
a2 = -46.1156297215959
a3 = 16.7162233502
a4 = -48.1321498860979
a5 = 98.3976323435346
a6 = -20.9828884928775
a7 = 52.3988150287754
a8 = 83.8147415646734
a9 = -98.3976323435346
a10 = 4.14985273584083
a11 = -60.6985205004571
a12 = -41.8489645789184
a13 = 77.5315562574938
a14 = -22.9994086573796
a15 = -66.9817058076367
a16 = -10.4330380430204
a17 = -73.2648911148163
a18 = 54.4153351932775
a19 = 4764.78779541347
a20 = 33.5492591072367
a21 = -8.41651787851834
a22 = 60.6985205004571
a23 = 8.41651787851834
a24 = 29.2825939645592
a25 = -14.6997031856979
a26 = 2.13333257133875
a27 = 27.2660738000571
a28 = -16.7162233502
a29 = -85.8312617291755
a30 = -2.13333257133875
a31 = 85.8312617291755
a32 = 35.5657792717388
a33 = 20.9828884928775
a34 = 71.2483709503142
a35 = 58.682000335955
a36 = 10.4330380430204
a37 = 39.8324444144163
a38 = 22.9994086573796
a39 = 92.114447036355
a40 = -4.14985273584083
a41 = -77.5315562574938
a42 = 64.9651856431346
a43 = 46.1156297215959
a44 = -52.3988150287754
a45 = -92.114447036355
a46 = -90.097926871853
a47 = 90.097926871853
a48 = -27.2660738000571
a49 = -35.5657792717388
a50 = -83.8147415646734
a51 = -79.5480764219959
a52 = -33.5492591072367
a53 = 96.3811121790326
a54 = 79.5480764219959
a55 = -39.8324444144163
a56 = 14.6997031856979
a57 = -96.3811121790326
a58 = -58.682000335955
a59 = 41.8489645789184
a60 = -71.2483709503142
a61 = -54.4153351932775
a62 = 48.1321498860979
a63 = -64.9651856431346
a64 = 73.2648911148163
a65 = 66.9817058076367
a66 = 211.494967872767