y=－2sin(π/3-x)=2sin(x-π/3)
所以 2kπ-π/2<=x-π/3<=2kπ+π/2(k是任意整数）时y递增
2kπ+π/2<=x-π/3<=2kπ+3π/2(k是任意整数）时y递减
所以2kπ-π/6<=x<=2kπ+5π/6(k是任意整数）时y递增
2kπ+5π/6<=x<=2kπ+11π/6(k是任意整数）时y递减