6.4(1)A
[0,2] [-π／２，π／２〕
４／５
－２／３
arc cos(-2/3)
[-π／２,0.2527]这答案有点怪

CBC

π/6
-π/2
-π/3
-根号2/5

x=arcsin(-1/3)
x=π - arcsin(-1/3)
x=arcsin1/4
x=π-arcsin1/4

Ymax=1 x=-π/2
Ymin =-3 x=π/2

6.4(2)A
5π/6
-π/6
π - arccos1/3
[-π/6,π/3]
[0,1/2]

CAA

x∈[3,3.5]

存在
y=arc cosx/2+1

5π/3 -5π/6

我好像错很多