等比数列{an}的各项为正数,且3是a5和a6的等比中项,则a1a2…a10=(  ) A.39 B.310 C.311 D.312

问题描述:

等比数列{an}的各项为正数,且3是a5和a6的等比中项,则a1a2…a10=(  )
A. 39
B. 310
C. 311
D. 312

∵等比数列{an}的各项为正数,且3是a5和a6的等比中项,
∴a5•a6=9,
则a1a2…a10=(a5 •a6)5=95=310
故选:B.