The teacher will be very surprised to see your correct solution 😉
sin(x)*cos(x) = 1/4
/ ___________\ | ___ / ___ | x1 = 2*atan\-2 + \/ 3 + 2*\/ 2 - \/ 3 /
/ ___________\ | ___ / ___ | x2 = -2*atan\2 - \/ 3 + 2*\/ 2 - \/ 3 /
/ ___________\ | ___ / ___ | x3 = -2*atan\2 + \/ 3 + 2*\/ 2 + \/ 3 /
/ ___________\ | ___ / ___ | x4 = -2*atan\2 + \/ 3 - 2*\/ 2 + \/ 3 /
x4 = -2*atan(-2*sqrt(sqrt(3) + 2) + sqrt(3) + 2)
sum
/ ___________\ / ___________\ / ___________\ / ___________\ | ___ / ___ | | ___ / ___ | | ___ / ___ | | ___ / ___ | 2*atan\-2 + \/ 3 + 2*\/ 2 - \/ 3 / - 2*atan\2 - \/ 3 + 2*\/ 2 - \/ 3 / - 2*atan\2 + \/ 3 + 2*\/ 2 + \/ 3 / - 2*atan\2 + \/ 3 - 2*\/ 2 + \/ 3 /
=
/ ___________\ / ___________\ / ___________\ / ___________\ | ___ / ___ | | ___ / ___ | | ___ / ___ | | ___ / ___ | - 2*atan\2 + \/ 3 - 2*\/ 2 + \/ 3 / - 2*atan\2 + \/ 3 + 2*\/ 2 + \/ 3 / - 2*atan\2 - \/ 3 + 2*\/ 2 - \/ 3 / + 2*atan\-2 + \/ 3 + 2*\/ 2 - \/ 3 /
product
/ ___________\ / ___________\ / ___________\ / ___________\ | ___ / ___ | | ___ / ___ | | ___ / ___ | | ___ / ___ | 2*atan\-2 + \/ 3 + 2*\/ 2 - \/ 3 /*-2*atan\2 - \/ 3 + 2*\/ 2 - \/ 3 /*-2*atan\2 + \/ 3 + 2*\/ 2 + \/ 3 /*-2*atan\2 + \/ 3 - 2*\/ 2 + \/ 3 /
=
/ ___________\ / ___________\ / ___________\ / ___________\ | ___ / ___ | | ___ / ___ | | ___ / ___ | | ___ / ___ | -16*atan\-2 + \/ 3 + 2*\/ 2 - \/ 3 /*atan\2 + \/ 3 - 2*\/ 2 + \/ 3 /*atan\2 + \/ 3 + 2*\/ 2 + \/ 3 /*atan\2 - \/ 3 + 2*\/ 2 - \/ 3 /
-16*atan(-2 + sqrt(3) + 2*sqrt(2 - sqrt(3)))*atan(2 + sqrt(3) - 2*sqrt(2 + sqrt(3)))*atan(2 + sqrt(3) + 2*sqrt(2 + sqrt(3)))*atan(2 - sqrt(3) + 2*sqrt(2 - sqrt(3)))
x1 = -75.1364242983559
x2 = 29.5833308213039
x3 = -1.83259571459405
x4 = 0.261799387799149
x5 = 73.565627971561
x6 = 12.8281700021583
x7 = 51.5744793964324
x8 = 15.9697626557481
x9 = -74.0892267471593
x10 = 13.8753675533549
x11 = -52.0980781720307
x12 = 72.5184304203644
x13 = -100.269165527074
x14 = 45.2912940892529
x15 = -67.8060414399797
x16 = 81.9432083811338
x17 = -53.1452757232273
x18 = 6.54498469497874
x19 = 34.8193185772869
x20 = 44.2440965380563
x21 = 4.45058959258554
x22 = -83.5140047079287
x23 = 50.5272818452358
x24 = -81.4196096055355
x25 = 9.68657734856853
x26 = 88.2263936883134
x27 = -17.540558982543
x28 = 26.4417381677141
x29 = -80.3724120543389
x30 = -59.4284610304069
x31 = 42.1497014356631
x32 = 28.5361332701073
x33 = 94.5095789954929
x34 = -9.16297857297023
x35 = -42.6733002112614
x36 = 79.8488132787406
x37 = -65.7116463375865
x38 = -36.3901149040818
x39 = 59.9520598060052
x40 = 20.1585528605345
x41 = 78.801615727544
x42 = 7.59218224617533
x43 = -86.6555973615185
x44 = -28.012534494509
x45 = -23.8237442897226
x46 = -8.11578102177363
x47 = 95.5567765466895
x48 = -55.2396708256205
x49 = 31.6777259236971
x50 = 53.6688744988256
x51 = 100.792764302673
x52 = -58.3812634792103
x53 = -40.5789051088682
x54 = -56.2868683768171
x55 = 35.8665161284835
x56 = -34.2957198016886
x57 = 56.8104671524154
x58 = -30.1069295969022
x59 = -21.7293491873294
x60 = -14.3989663289532
x61 = -12.30457122656
x62 = -89.7971900151083
x63 = -87.7027949127151
x64 = -71.9948316447661
x65 = 57.857664703612
x66 = 75.6600230739542
x67 = -15.4461638801498
x68 = -31.1541271480988
x69 = -61.5228561328001
x70 = -39.5317075576716
x71 = 37.9609112308767
x72 = -43.720497762458
x73 = -45.8148928648512
x74 = 48.4328867428426
x75 = -96.0803753222878
x76 = -6.02138591938044
x77 = -64.6644487863899
x78 = -694.030177055545
x79 = 66.2352451131848
x80 = -37.4373124552784
x81 = 86.1319985859202
x82 = -50.0036830696375
x83 = 64.1408500107916
x84 = -97.1275728734844
x85 = -78.2780169519457
x86 = 22.2529479629277
x87 = 70.4240353179712
x88 = 92.4151838930998
x89 = -93.9859802198946
x89 = -93.9859802198946