Question

已知2^a=3,2^b=6,2^c=12,则a,b,c

1. A.
   成等差数列但不成等比数列
2. B.
   成等比数列但不成等差数列
3. C.
   既成等差数列又成等比数列
4. D.
   既不成等比数列又不成等差数列

Answer 1

A
∵a=log₂3,b=log₂6,c=log₂12,又∵log₂3+log₂12=log₂36=2log₂6,∴2b=a+c.故a,b,c成等差数列但不成等比数列.