cos4x+cos2x=0
√3 sin3x+cos3x=1

2x=acos(2a)+cos(a)=0cosˆ2(a)-sinˆ2(a)+cos(a)=02cosˆ2(a)-1+cos(a)=0cos(a)=x2xˆ2+x-1=0D=1+8=9x=cos(a)=(-1+/-3)/4=-1; 1/2cos(a)=-1cos(a)=1/2a=Pi+2*Pi*n2x=Pi+2*Pi*nx=Pi/2+Pi*ncos(a)=1/22x=a=Pi/3+2Pi*nx=Pi/6+Pi*n2) sqrt(3)* sin3x+cos3x=12*(1/2 *sqrt(3)*sin3x + 1/2*cos3x)=12*(sin(pi/6)*cos3x+cos(pi/6)*sin3x)=12*(sin(3x+Pi/6))=1sin(3x+Pi/6)=1/23x+Pi/6=Pi/6+2Pi*n3x=2Pi*nx=2Pi*n/3