1)3SIN2X+COS2X+1=0 3*2sinx*cosx+cos^2x-sin^2x+sin^2x+cos^2x=0 6sinx*cosx+2cos^2x=0 2cosx(cosx+6sinx)=0
2cosx=0 cosx=0 x=pi/2+pi*n
cosx+6sinx=0/cosx 1+6tgx=0 6tgx=-1 tgx=-1/ 6 x=arctg(-1/6)+pi*n
2)sin5x+sinx+2sin(2x)=1 sin5x+sinx=1-2sin^2x sin5x+sinx=cos2x sin5x+sinx=2sin(5x+x)/2*(cos(5x-x)/2)=2sin3x*cos2x =>2sin3x*cos2x=cos2x
cos2x(2sin3x-1)=0 cosx=0 2sin3x-1=0
x1=pi/2+pi*n sin3x=1/2 3x=pi/6+2pi*n 3x=5pi/6+2pi*n x2=pi/18+2/3pi*n x3=5pi/18+2/3pi*n n ( Z