Question

設(shè)a=log32，b=log23，c=log

1

2

1

5

，則（　�。�

A．a(chǎn)＜b＜c

B．a(chǎn)＜c＜b

C．b＜a＜c

D．b＜c＜a

Answer 1

∵log₃1＜a=log₃2＜log₃3∴0＜a＜1
∵b=log₂3＞log₂2=1∴b＞1
∵c=log

1

2

1

5

＞log

1

2

1

2

= 1∴c＞1
∵∵c=log

1

2

1

5

= log25＞log23=b      即c＞b
故有c＞b＞a
故選A