是不是srcsin(x-2/3)
arcsin定义域是[-1,1]
-1是arcsin3分之x-2.-1<=(x-2)/3<=1解出x即可看不懂你的-1/3<=x<=5/3是怎么来得啊-1<=(x-2)/3<=1-3<=x-2<=3-1<=x<=5