设F(x)=ax+b
F[F(x)]
=a(ax+b)+b
=9x+8
所以9x=a(ax+b),b=8,
将b=8代入9x=a(ax+b),
9x=a(ax+8)
9x=a方x+8a
0=a方x+8a-9x
a=[-4+(4-3x)]/x或x=[-4-(4-3x)]/x
y=log 2 (x/4) * log 4 (x/2)
=log 2 (x/2) * log 2方 (x/2)
=[ log 2 (x/4) * log 2 (x/2) ]/2
=[一个设为G的数*一个设为H的数]/2
先看G这边,log 2 (x/4),
当x=2时log 2 (2/4)=log 2 (1/2)=1
当x=3时log 2 (3/4)
当x=4时log 2 (4/4)=0
在看H这边,log 2 (x/2)
当x=2时log 2 (2/2)=0
当x=3时log 2 (4/3)
当x=4时log 2 (4/2)=1
值域=[0.5,1]