The teacher will be very surprised to see your correct solution 😉
2 sin(2*x) + 16*cos (x) = 4
/log(5) / ___\\ x1 = -pi + I*|------ - log\\/ 5 /| + atan(2) \ 2 /
/log(5) / ___\\ x2 = I*|------ - log\\/ 5 /| + atan(2) \ 2 /
/log(13) / ____\\ x3 = pi - atan(3/2) + I*|------- - log\\/ 13 /| \ 2 /
/log(13) / ____\\ x4 = -atan(3/2) + I*|------- - log\\/ 13 /| \ 2 /
x4 = -atan(3/2) + i*(-log(sqrt(13)) + log(13)/2)
sum
/log(5) / ___\\ /log(5) / ___\\ /log(13) / ____\\ /log(13) / ____\\ -pi + I*|------ - log\\/ 5 /| + atan(2) + I*|------ - log\\/ 5 /| + atan(2) + pi - atan(3/2) + I*|------- - log\\/ 13 /| + -atan(3/2) + I*|------- - log\\/ 13 /| \ 2 / \ 2 / \ 2 / \ 2 /
=
/log(5) / ___\\ /log(13) / ____\\ -2*atan(3/2) + 2*atan(2) + 2*I*|------ - log\\/ 5 /| + 2*I*|------- - log\\/ 13 /| \ 2 / \ 2 /
product
/ /log(5) / ___\\ \ / /log(5) / ___\\ \ / /log(13) / ____\\\ / /log(13) / ____\\\ |-pi + I*|------ - log\\/ 5 /| + atan(2)|*|I*|------ - log\\/ 5 /| + atan(2)|*|pi - atan(3/2) + I*|------- - log\\/ 13 /||*|-atan(3/2) + I*|------- - log\\/ 13 /|| \ \ 2 / / \ \ 2 / / \ \ 2 // \ \ 2 //
=
/ 2 \ \pi + atan(2)*atan(3/2) - pi*atan(2) - pi*atan(3/2)/*atan(2)*atan(3/2)
(pi^2 + atan(2)*atan(3/2) - pi*atan(2) - pi*atan(3/2))*atan(2)*atan(3/2)
x1 = 39.85791077342
x2 = 54.5142238288206
x3 = -2.0344439357957
x4 = -74.2910749683609
x5 = 33.5747254662404
x6 = -68.0078896611814
x7 = 24.149947505471
x8 = 46.1410960805996
x9 = 63.93900178959
x10 = -33.4503704716936
x11 = 60.7974091360002
x12 = 68.1322446557281
x13 = -54.3898688342738
x14 = 32.523075253692
x15 = 38.8062605608716
x16 = 76.5053724039491
x17 = 99.5481711916261
x18 = 74.4154299629077
x19 = -82.664202716582
x20 = 8.44198423752205
x21 = -32.3987202591453
x22 = 52.4242813877792
x23 = 27.2915401590608
x24 = 11.5835768911118
x25 = -48.1066835270942
x26 = 85.9301503647185
x27 = -77.4326676219507
x28 = 26.2398899465124
x29 = 70.2221870967695
x30 = 90.1233932308567
x31 = 48.231038521641
x32 = -63.8146467950432
x33 = -13.5491643376065
x34 = -76.3810174094024
x35 = -93.1406308898997
x36 = -41.8234982199146
x37 = -49.1583337396426
x38 = -39.7335557788732
x39 = 4.24874137138388
x40 = -8.31762924297529
x41 = -30.3087778181038
x42 = -4.12438637683712
x43 = 17.8667621982914
x44 = -79.5226100629922
x45 = 2.15879893034246
x46 = 35.6646679072818
x47 = -89.9990382363099
x48 = 30.4331328126506
x49 = -98.3721659845309
x50 = -17.7424072037447
x51 = -96.2822235434895
x52 = 57.6558164824104
x53 = 41.9478532144614
x54 = -85.8057953701718
x55 = -60.6730541414534
x56 = -55.4415190468222
x57 = 96.4065785380363
x58 = 13.6735193321533
x59 = 61.8490593485485
x60 = -36.5919631252834
x61 = 55.565874041369
x62 = -10.4075716840167
x63 = 101.638113632667
x64 = -61.7247043540018
x65 = -26.1155349519657
x66 = -19.8323496447861
x67 = -46.0167410860528
x68 = -35.5403129127351
x69 = -27.167185164514
x70 = 83.8402079236771
x71 = -11.4592218965651
x72 = -24.0255925109243
x73 = 16.8151119857431
x74 = -57.5314614878636
x75 = -92.0889806773513
x76 = 77.5570226164975
x77 = 19.9567046393328
x78 = 92.2133356718981
x79 = -5.1760365893855
x80 = 10.5319266785635
x81 = 98.4965209790777
x82 = -71.1494823147711
x83 = -70.0978321022228
x84 = -99.4238161970793
x85 = -52.2999263932324
x86 = 82.7885577111287
x87 = -83.7158529291303
x87 = -83.7158529291303