已知A,B,A+B成等差数列,A,B,AB成等比数列,且0<logmAB<1,则m的取值范围是( )
A.m>1 B.1<m<8 C.m>8 D.0<m<1或m>8 麻烦写写解题思路`
參考答案:0<logmAB<1 AB>0
A,B,A+B成等差数列
2B=2A+B B=2A
A,B,AB成等比数列
B^2=A^2*B
B=A^2=B^2/4 B=4
则A=2
AB=8
0<logm8 m>1
logm 8<logm m
m>8
C
已知A,B,A+B成等差数列,A,B,AB成等比数列,且0<logmAB<1,则m的取值范围是( )
A.m>1 B.1<m<8 C.m>8 D.0<m<1或m>8 麻烦写写解题思路`
參考答案:0<logmAB<1 AB>0
A,B,A+B成等差数列
2B=2A+B B=2A
A,B,AB成等比数列
B^2=A^2*B
B=A^2=B^2/4 B=4
则A=2
AB=8
0<logm8 m>1
logm 8<logm m
m>8
C