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斐波那契1 1 2 3 5 8.怎么证明前后比值无限接近0.618.

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斐波那契1 1 2 3 5 8.怎么证明前后比值无限接近0.618.
斐波那契数列通项公式F(n)=(1/√5)*{[(1+√5)/2]^n - [(1-√5)/2]^n}
F(n)/F(n+1)= {[(1+√5)/2]^n - [(1-√5)/2]^n}/{[(1+√5)/2]^(n+1) - [(1-√5)/2]^(n+1)}
lim(n→∞)F(n)/F(n+1)
=lim(n→∞){[(1+√5)/2]^n - [(1-√5)/2]^n}/{[(1+√5)/2]^(n+1) - [(1-√5)/2]^(n+1)}
=lim(n→∞)[(1+√5)/2]^n /[(1+√5)/2]^(n+1)
=1/[(1+√5)/2]
=(√5-1)/2
=0.618