已知函数f(x)=(2x+3)/(3x)(x>0),数列{an}满足a1=1,an=f(1/an-1)(n∈N*,且n》2.
1.求an的通项公式.2.求Sn=a1a2-a2a3+a3a4-a4a5+.+anan+1
人气:162 ℃ 时间:2019-08-19 16:17:33
解答
(1)根据f(x)=(2x+3)/(3x)可把an=f(1/a(n-1))化为an=a(n-1)+2/3所以an是以2/3为公差的等差数列又a1=1所以解得an=2n/3+1/3(2)a1a2-a2a3+a3a4-a4a5+.+anan+1可化为a2(a1-a3)+a4(a3-a5)+a6(a5-a7)+.+a(n-1)(a(n-2)+an)+a...
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