sin(п/2+х)=cosx) поэтому8sin^2(x)+6cos(x)=98(1-cos^2(x))+6cos(x)=98-8cos^2(x)+6cos(x)=98cos^2(x)-6cos(x)+1=0D=36-4*8*1=4cos(x)=(6-2)/2*8 cos(x)=(6+2)/2*8cos(x)=1/4 cos(x)=1/2x=arccos(1/4) x=arccos(1/2)=п/3+2пк
sin(п/2+х)=cosx) поэтому
8sin^2(x)+6cos(x)=9
8(1-cos^2(x))+6cos(x)=9
8-8cos^2(x)+6cos(x)=9
8cos^2(x)-6cos(x)+1=0
D=36-4*8*1=4
cos(x)=(6-2)/2*8 cos(x)=(6+2)/2*8
cos(x)=1/4 cos(x)=1/2
x=arccos(1/4) x=arccos(1/2)=п/3+2пк