SinxCosy = t
SinyCosx = z
6t + 2z = -3|*3 18t - 6z = -9
5t - 3z= 1|*2 10t -6z = 2 сложим
28t = -7
t = -1/4
5t -3z = 1
5*(-1/4) - 3z = 1
3z = -5/4 -1
3z = -9/4
z = -3/4
SinxCosy = -1/4
CosxSiny = -3/4 сложим
SinxCosy + CosxSiny = -1
Sin(x+y) = -1
x+y = -ЄZ
SinxCosy = -1/4
CosxSiny = -3/4 вычтем:
SinxCosy - CosxSiny = 1/2
Sin(x-y) = 1/2
x - y = (-1)^n
решаем новую систему сложением...
при х = - 0,1
20х3 - 6х2<span> + 3=20·(-0,1)³-6·(-0,1)²+3=20·(-0,001)-6·0,01+3=-0,02-0,06+3=2,92</span>