0x=0
Ответ х - любое
:sin²x
7-10ctgx+3ctg²x=0
ctgx=t
3t²-10t+7=0
D=100-84=16
√D=4
t1=10-4/6=1
t2=14/6=7/3
ctgx=1
x=π/4 +πn
ctgx=7/3
x=arccth 7/3 + πn
1) 5t+11 = 7t + 31, 2t = -20, t = -10.