(1/2)*a1+(1/2^2)a2+……+(1/2^(n-1))*a(n-1)+(1/2^n)*an=5+2n……式子1 (1/2)*a1+(1/2^2)a2+……+(1/2^(n-1))*a(n-1=5+2(n-1)……式子2 式子1-式子2=(1/2^n)*an=2 an=2^(n+1) 令bn=1/an=1/2^(n+1) Tn=((1/4)*(1-1/2^n))/(1-1/2) =(1-2^n)/2
数列{an}满足(1/2)*a1+(1/2^2)a2+……(1/2^n)*an=5+2n（n∈N*)
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