已知实数x,y满足x^2+y^2=1,则x+y的取值范围是---;x-√3y的取值范围是---

令x=cosa y=sina
x+y=cosa+sina=√2sin(x+π/4)
-1≤sin(x+π/4)≤1
-√2≤x+y≤√2
x-√3y=cosa-√3sina=2[cosasin(π/6)-cos(π/6)sina]=2sin(π/6-a)
-1≤sin(π/6-a)≤1
-2≤x-√3y≤2
已知实数x,y满足x^2+y^2=1,则x+y的取值范围是( [-√2,√2] )；
x-√3y的取值范围是( [-2,2] ).