bn=1/an=1/(n^2+3n+2)=1/[(n+1)(n+2)]=1/(n+1)-1/(n+2)
S10=b1+b2+...+b10
=1/2-1/3+1/3-1/4+...+1/11-1/12
=1/2-1/12
=5/12
数列an,bn满足anbn=1,an=n²+3n+2,则bn的前十项之和是?
数列an,bn满足anbn=1,an=n²+3n+2,则bn的前十项之和是?
数学人气:630 ℃时间:2019-10-05 13:48:32
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