举报
真实11
抱歉,真做错了 利用诱导公式简化 y=sin(2x+6分之π)+cos(2x+三分之π) = sin(2x+π/6)+cos[(π/2)-(-2x+π/6)] = sin(2x+π/6)+sin(-2x+π/6) =sin(2x+π/6)-sin(2x-π/6) =sin2x*cos(π/6)+cos2x*sin(π/6)-sin2x*cos(π/6)+cos2x*sin(π/6) = 2sin(π/6)cos2x =cos2x ∴ 最小正周期是T=2π/2=π 最大值是1 有答案啊,选A