cos(x)/cos(2*x)=6,得到cos(x)/[2*(cos(x))^2-1]=6,
变形整理为12*(cos(x))^2-6=cos(x),
即12*(cos(x))^2-cos(x)-6=0,
解得cos(x)=-2/3(x为锐角,故舍去),或cos(x)=3/4.
sin(x)/sin(2*x)=1/(2*cos(x))=1/[2*(3/4)]=2/3
cos(x)/cos(2*x)=6,得到cos(x)/[2*(cos(x))^2-1]=6,
变形整理为12*(cos(x))^2-6=cos(x),
即12*(cos(x))^2-cos(x)-6=0,
解得cos(x)=-2/3(x为锐角,故舍去),或cos(x)=3/4.
sin(x)/sin(2*x)=1/(2*cos(x))=1/[2*(3/4)]=2/3