（1）∵ -π/6＜x＜π/6∴-π/3＜2x＜π/3∴0＜2x+π/3＜2π/3当t∈（0,2π/3）时,y=sint的取值范围是(0,1]∴y=2sint的取值范围是(0,2]即y＝2sin(2x＋π/3)的值域是(0,2]（2）y=2cos²x＋5sinx-4=2(1-sin²x...