The teacher will be very surprised to see your correct solution 😉
4*cos(2*x) - 9*sin(x) - 4 ------------------------- = 0 _________ \/ -cos(x)
x1 = 0
x2 = pi
/ 2\ |/ ____\ | |\9 - \/ 17 / | I*log|-------------| pi \ 64 / x3 = - -- - -------------------- 2 2
/ 2\ |/ ____\ | |\9 + \/ 17 / | I*log|-------------| pi \ 64 / x4 = - -- - -------------------- 2 2
x4 = -pi/2 - i*log((sqrt(17) + 9)^2/64)/2
sum
/ 2\ / 2\ |/ ____\ | |/ ____\ | |\9 - \/ 17 / | |\9 + \/ 17 / | I*log|-------------| I*log|-------------| pi \ 64 / pi \ 64 / pi + - -- - -------------------- + - -- - -------------------- 2 2 2 2
=
/ 2\ / 2\ |/ ____\ | |/ ____\ | |\9 + \/ 17 / | |\9 - \/ 17 / | I*log|-------------| I*log|-------------| \ 64 / \ 64 / - -------------------- - -------------------- 2 2
product
/ / 2\\ / / 2\\ | |/ ____\ || | |/ ____\ || | |\9 - \/ 17 / || | |\9 + \/ 17 / || | I*log|-------------|| | I*log|-------------|| | pi \ 64 /| | pi \ 64 /| 0*pi*|- -- - --------------------|*|- -- - --------------------| \ 2 2 / \ 2 2 /
=
0
0
x1 = -97.3893722612836
x2 = -43.9822971502571
x3 = -95.8185759344887 - 0.494932923094527*i
x4 = -78.5398163397448
x5 = 56.5486677646163
x6 = 28.2743338823081
x7 = -81.6814089933346
x8 = -15.707963267949
x9 = 72.2566310325652
x10 = -53.4070751110265
x11 = -106.814150222053
x12 = -18.8495559215388
x13 = -39.2699081698724 + 0.494932923094527*i
x14 = 50.2654824574367
x15 = 25.1327412287183
x16 = 100.530964914873
x17 = -9.42477796076938
x18 = 81.6814089933346
x19 = 69.1150383789755
x20 = -21.9911485751286
x21 = 53.4070751110265
x22 = -91.106186954104
x23 = -72.2566310325652
x24 = 15.707963267949
x25 = 40.8407044966673
x26 = -28.2743338823081
x27 = -62.8318530717959
x28 = -6.28318530717959
x29 = 3.14159265358979
x30 = -75.398223686155
x31 = -25.1327412287183
x32 = -7.85398163397448 - 0.494932923094527*i
x33 = -84.8230016469244
x34 = 42.4115008234622 + 0.494932923094527*i
x35 = 59.6902604182061
x36 = 36.1283155162826 - 0.494932923094527*i
x37 = -87.9645943005142
x38 = -34.5575191894877
x39 = -51.8362787842316 - 0.494932923094527*i
x40 = 31.4159265358979
x41 = 0.0
x42 = -65.9734457253857
x43 = 47.1238898038469
x44 = 18.8495559215388
x45 = 84.8230016469244
x46 = 91.106186954104
x47 = 6.28318530717959
x48 = -1.5707963267949 - 0.494932923094527*i
x49 = -47.1238898038469
x50 = 94.2477796076938
x51 = 65.9734457253857
x52 = -56.5486677646163
x53 = 21.9911485751286
x54 = 80.1106126665397 - 0.494932923094527*i
x55 = 78.5398163397448
x56 = 75.398223686155
x57 = 87.9645943005142
x58 = 12.5663706143592
x59 = -3.14159265358979
x60 = -37.6991118430775
x61 = -12.5663706143592
x62 = 97.3893722612836
x63 = -100.530964914873
x64 = 43.9822971502571
x65 = -50.2654824574367
x66 = 37.6991118430775
x67 = -40.8407044966673
x68 = -59.6902604182061
x69 = -69.1150383789755
x70 = 9.42477796076938
x71 = 62.8318530717959
x72 = -94.2477796076938
x73 = 34.5575191894877
x74 = -31.4159265358979
x74 = -31.4159265358979