sin2x+cos2x=根号2sin(2x+pi/4)
函数y=cos(x-pai/8)x取2/3pai取最小值
y=cos(2/3pai-pai/8)=y=cos(13/24pai)=cos(1/2pqi-1/24pai)=sin(1/24pai)=sin(7.5度)
计算这个建议用计算机
sin2x+cos2x=根号2sin(2x+pi/4)
函数y=cos(x-pai/8)x取2/3pai取最小值
y=cos(2/3pai-pai/8)=y=cos(13/24pai)=cos(1/2pqi-1/24pai)=sin(1/24pai)=sin(7.5度)
计算这个建议用计算机