> 数学 >
数列{an}满足下列条件:a1=1,且对于任意的正整数n,恒有a2n=an+n,a512=(  )
A. 128
B. 256
C. 512
D. 1024
人气:119 ℃ 时间:2020-04-16 16:58:45
解答
因为对于任意的正整数n,恒有a2n=an+n,
所以:a512=a256+256=a256+28
=a128+128+256=a128+27+28
=a64+26+27+28
=…
=a2+22+23+…+28
=a1+1+21+22+…+28
=1+1+21+22+…+28
=1+
1−29
1−2
=512.
故选C.
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