cos(a;b)=(x₁*x₂+y₁*y₂)/(|a|*|b|)
|a|=√(64+49+4)=√117 , |b|=√(36+9+64)=√109
a*b=-8*6+7*3+(-2)*(-8)=-11
cos(a;b)=-11/(√(117×109)<0 тупой
cos(a;b)=(x₁*x₂+y₁*y₂)/(|a|*|b|)
|a|=√(64+49+4)=√117 , |b|=√(36+9+64)=√109
a*b=-8*6+7*3+(-2)*(-8)=-11
cos(a;b)=-11/(√(117×109)<0 тупой