已知a1=3,a(n+1)=(3n-1)/(3n+2)an(n≥1),求an

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已知a1=3,a(n+1)=(3n-1)/(3n+2)an(n≥1),求an

已知a1=3,a(n+1)=(3n-1)/(3n+2)an(n≥1),求an
已知a1=3,a(n+1)=(3n-1)/(3n+2)an(n≥1),求an

已知a1=3,a(n+1)=(3n-1)/(3n+2)an(n≥1),求an
a2/a1=2/5,
a3/a2=5/8,
a4/a3=8/11,
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an+1/an=(3n-1)/(3n+2)
左相乘:(a2/a1)(a3/a2)(a4/a3)……(an+1/an)=右相乘:2/5 5/8 8/11……(3n-1)/(3n+2),
an+1/a1=2/(3n+2),
an+1/3=2/(3n+2),
an+1=6/(3n+2),
an=6/(3n-1).