题目内容
等比数列{an}的各项均为正数,且a3a10+a6a7=8,则log2a1+log2a2+…+log2a12=( )
| A、2 | B、18 | C、12 | D、-8 |
分析:由题意可得 a6a7 =4,则log2a1+log2a2 +…+log2a12 =
=6
,运算求得结果.
| log | (a6a7)6 2 |
| log | a6a7 2 |
解答:解:由题意可得 a6a7 =4,
则log2a1+log2a2 +…+log2a12 =
=6
=6log24=12,
故选 C.
则log2a1+log2a2 +…+log2a12 =
| log | (a6a7)6 2 |
| log | a6a7 2 |
故选 C.
点评:本题考查等比数列的性质,对数的运算性质的应用,得到 a6a7 =4,是解题的关键.
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