2sinwx=-2
sinwx=-1
wx=3π/2+2kπ k为整数
w=(3π/2+2kπ)/x
(3π/2)/(-π/3)≤w+2kπ≤(3π/2)/(π/4)
-9/2≤w+2kπ≤6
-9/2-2kπ ≤w≤6-2kπ