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问题: 简单的数学问题,求解

在数列{An}中,已知A1=2,(A n+1) +(A n+1)An= 2An,对于任意正整数n,An不等于0.


求数列通向公式

解答:

在数列{An}中,已知A1 = 2,A(n+1) + A(n+1)An = 2An,对于任意正整数n,An不等于0。求数列通项公式。

A(n+1) + A(n+1)An = 2An
A(n+1)(An + 1) = 2An
A(n+1) = 2An/(1 + An)

A1 = 2
A2 = 2×2/(1 + 2) = 4/3
A3 = 2×(4/3)/(1 + 4/3) = 8/7
A3 = 2×(8/7)/(1 + 8/7) = 16/15
A4 = 2×(16/15)/(1 + 16/15) = 32/31
......
An = 2^n/(2^n - 1)