等比数列{an}满足:a1a2a3=2,a4a5a6=4,求a7a9=?

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等比数列{an}满足:a1a2a3=2,a4a5a6=4,求a7a9=?
等比数列{an}满足:a1a2a3=2,a4a5a6=4,求a7a9=?

等比数列{an}满足:a1a2a3=2,a4a5a6=4,求a7a9=?
a1a2a3=a2a2a2=2
a4a5a6=a5a5a5=4
a7a8a9=a8a8a8
a2a8=a5a5,所以a8a8a8=8
a7a9=a8a8=4