1-2*cos(3*x)=0

Перенесём 1 в правую часть ур-ния

с изменением знака при 1

Получим:
$$- 2 cos{left (3 x right )} = -1$$

Разделим обе части ур-ния на -2

Ур-ние превратится в
$$cos{left (3 x right )} = frac{1}{2}$$
Это ур-ние преобразуется в
$$3 x = pi n + {acos}{left (frac{1}{2} right )}$$
$$3 x = pi n – pi + {acos}{left (frac{1}{2} right )}$$
Или
$$3 x = pi n + frac{pi}{3}$$
$$3 x = pi n – frac{2 pi}{3}$$
, где n – любое целое число
Разделим обе части полученного ур-ния на
$$3$$
получим ответ:
$$x_{1} = frac{pi n}{3} + frac{pi}{9}$$
$$x_{2} = frac{pi n}{3} – frac{2 pi}{9}$$

pi
x1 = —
9

5*pi
x2 = —-
9

x1 = 100.181899064000

x2 = 75.7472895366000

x3 = 23.3874119767000

x4 = -52.0108117094000

x5 = 95.9931088597000

x6 = 20.5948851735000

x7 = 31.7649923863000

x8 = -75.7472895366000

x9 = -58.2939970166000

x10 = 47.8220215046000

x11 = -75.0491578358000

x12 = 70.8603676310000

x13 = -40.1425727959000

x14 = -12.9154364648000

x15 = -8.02851455917000

x16 = -84.1248699461000

x17 = 26.8780704807000

x18 = -95.9931088597000

x19 = -29.6705972839000

x20 = 5.93411945678000

x21 = 77.8416846389000

x22 = -104.370689269000

x23 = -23.3874119767000

x24 = -79.9360797413000

x25 = -27.5762021815000

x26 = -31.7649923863000

x27 = -89.7099235525000

x28 = -100.181899064000

x29 = 93.8987137573000

x30 = 58.2939970166000

x31 = 56.1996019142000

x32 = 16.4060949687000

x33 = -82.0304748437000

x34 = -1.74532925199000

x35 = 46.4257581030000

x36 = -98.0875039621000

x37 = -10.1229096616000

x38 = 88.3136601509000

x39 = -77.8416846389000

x40 = -3.83972435439000

x41 = -68.7659725286000

x42 = -93.8987137573000

x43 = 38.0481776935000

x44 = -87.6155284501000

x45 = -38.0481776935000

x46 = 64.5771823238000

x47 = 52.0108117094000

x48 = -35.9537825911000

x49 = -5.93411945678000

x50 = 73.6528944342000

x51 = 33.8593874887000

x52 = -45.7276264023000

x53 = -20.5948851735000

x54 = 82.0304748437000

x55 = 0.349065850399000

x56 = 40.1425727959000

x57 = 54.1052068118000

x58 = 86.2192650485000

x59 = 3.83972435439000

x60 = 10.1229096616000

x61 = 60.3883921190000

x62 = -54.1052068118000

x63 = 90.4080552533000

x64 = -67.3697091270000

x65 = 84.1248699461000

x66 = -43.6332312999000

x67 = -47.8220215046000

x68 = -91.8043186549000

x69 = -71.5584993318000

x70 = -2150248.78005000

x71 = -33.8593874887000

x72 = -25.4818070791000

x73 = -60.3883921190000

x74 = -16.4060949687000

x75 = -12.2173047640000

x76 = -73.6528944342000

x77 = -69.4641042294000

x78 = 44.3313630007000

x79 = 18.5004900711000

x80 = -56.1996019142000

x81 = 29.6705972839000

x82 = -14.3116998664000

x83 = 14.3116998664000

x84 = 12.2173047640000

x85 = 62.4827872214000

x86 = 98.0875039621000

x87 = -49.9164166070000

x88 = 42.2369678983000

x89 = 79.9360797413000

x90 = 49.9164166070000

x91 = 8.02851455917000

x92 = 35.9537825911000