Именно так;.x1=5;X2=-3; сумма их ровна 2
(-oo < x, x < oo)Даю 30 баллов!
Cos158=cos(180-2*11)=-cos 2*11=cos²11-sin²11=1-2sin²11=1-2*a
cos158=1-2a²
<span>1-cosx=2*sin(x\2) </span>
<span>2sin²(x/2)-2sin(x/2)=0 </span>
<span>sin(x/2)(sin(x/2)-1)=0 </span>
<span>a) sin(x/2)=0 </span>
<span>x/2=πn </span>
<span>x1=2πn </span>
<span>б) </span>
<span>sin(x/2)-1=0 </span>
<span>sin(x/2)=1 </span>
<span>x/2=π/2+2πn </span>
<span>x2=πn+4πn</span>