问题
选择题
各项均为正数的等比数列{bn}中,若b7•b8=9,则log3b1+log3b2++log3b14=( )
A.7
B.9
C.14
D.18
答案
∵等比数列{bn}中b7•b8=9,
∴log3b1+log3b2+…+log3b14=log 3(b1b2…b14)
=log 3(b7b8)7=log 3 97=14,
故选C.
各项均为正数的等比数列{bn}中,若b7•b8=9,则log3b1+log3b2++log3b14=( )
A.7
B.9
C.14
D.18
∵等比数列{bn}中b7•b8=9,
∴log3b1+log3b2+…+log3b14=log 3(b1b2…b14)
=log 3(b7b8)7=log 3 97=14,
故选C.