观察下面的数:(1)-3,9,-27,81,-243,729.(2)0,12,-24,84,-243,729.(3)-1

学习时间:2026-09-26 01:23:24 阅读：9870

观察下面的数:(1)-3,9,-27,81,-243,729.(2)0,12,-24,84,-243,729.(3)-1,3,-9,27,-81,243.取每行第10个数,计算这3个数的和

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2026-09-26 01:23:24

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第二个数列好像有点问题:(1)-3,9,-27,81,-243,729。数列为(-1)^n *3^n 3^102)0,12,-24,84,-243,729。数列为3)-1,3,-9,27,-81,243……数列为 (-1)^(n) *3^(n-1) 3^9