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Let the sequence an satisfy a1 + 3a2 + 3 & # 178; A3 + +3 ^ n-1 (an) = n / 3, find the general term formula of sequence an
When n = 1, A1 = 1 / 3N > 1, a1 + 3a2 +... + 3 ^ (n-2) a (n-1) + 3 ^ (n-1) an = n / 3, ① a1 + 3a2 +... + 3 ^ (n-2) a (n-1) = (n-1) / 3, ② ① - ② get 3 ^ (n-1) an = n / 3 - (n-1) / 3 = 1 / 3, ｜ an = 1 / 3 × (1 / 3) ^ (n-1) = (1 / 3) ^ n, when n = 1, the general term is an = (1 / 3) ^ n = 1 /
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