Sinx*cos(x+pi/3)+cosx*sin(x+pi/3)=0
Sinx*cos(x+π/3)+cosx*sin(x+π/3) =0 ; * * * sinαcosβ +cosα*sinβ =sin(α+β) * * * sin(x+x+π/3) =0 ; sin(2x+π/3) =0 ; 2x+π/3 =πk , k∈Z. 2x= -π/3 +πk , k∈Z. x= -π/6 +(π/2)*k , k∈Z.