The teacher will be very surprised to see your correct solution 😉
/ 3*pi\ sin|x + ----| = 0 \ 4 /
with the change of sign in 0
sum
pi 5*pi -- + ---- 4 4
=
3*pi ---- 2
product
pi 5*pi --*---- 4 4
=
2 5*pi ----- 16
5*pi^2/16
pi x1 = -- 4
5*pi x2 = ---- 4
x2 = 5*pi/4
x1 = 63.6172512351933
x2 = -65.1880475619882
x3 = 47.9092879672443
x4 = 76.1836218495525
x5 = 57.3340659280137
x6 = 44.7676953136546
x7 = -11.7809724509617
x8 = -8.63937979737193
x9 = -62.0464549083984
x10 = -40.0553063332699
x11 = 3.92699081698724
x12 = 29.0597320457056
x13 = -1535.45340944201
x14 = 38.484510006475
x15 = -228.550865548657
x16 = 13.3517687777566
x17 = -30.6305283725005
x18 = 32.2013246992954
x19 = 7.06858347057703
x20 = -43.1968989868597
x21 = -33.7721210260903
x22 = 88.7499924639117
x23 = -49.4800842940392
x24 = -58.9048622548086
x25 = -68.329640215578
x26 = 98.174770424681
x27 = -24.3473430653209
x28 = 35.3429173528852
x29 = 69.9004365423729
x30 = 85.6083998103219
x31 = 1672.11268987317
x32 = -27.4889357189107
x33 = 54.1924732744239
x34 = -84.037603483527
x35 = 19.6349540849362
x36 = 10.2101761241668
x37 = 41.6261026600648
x38 = 79.3252145031423
x39 = -14.9225651045515
x40 = -46.3384916404494
x41 = -5.49778714378214
x42 = -96.6039740978861
x43 = 60.4756585816035
x44 = 51.0508806208341
x45 = 25.9181393921158
x46 = -90.3207887907066
x47 = -74.6128255227576
x48 = -55.7632696012188
x49 = 22.776546738526
x50 = 95.0331777710912
x51 = -93.4623814442964
x52 = -2.35619449019234
x53 = -71.4712328691678
x54 = -52.621676947629
x55 = -99.7455667514759
x56 = 66.7588438887831
x57 = -18.0641577581413
x58 = 0.785398163397448
x59 = 91.8915851175014
x60 = -36.9137136796801
x61 = -80.8960108299372
x62 = 101.316363078271
x63 = -87.1791961371168
x64 = 82.4668071567321
x65 = -21.2057504117311
x66 = 73.0420291959627
x67 = 16.4933614313464
x68 = -77.7544181763474
x68 = -77.7544181763474