点(An+1,Sn)在直线2x+y-2=0上,表明Sn=y=2-2x=2-2An+1
S1=A1=1=2-2A2,A2=1/2
S2=A1+A2=3/2=2-2A3,A3=1/4
以此类推,A4=1/8,A5=1/16,...An=1/2^(n-1)
Sn为等比数列,其通项为 Sn=2-2/2^n
Sn+P*n+P/2∧n=2-2/2^n+Pn+P/2^n,要使该数列为等差数列,需消去1/2^n项,即 P=2,此时该数列为 2+2n,是等差数列
点(An+1,Sn)在直线2x+y-2=0上,表明Sn=y=2-2x=2-2An+1
S1=A1=1=2-2A2,A2=1/2
S2=A1+A2=3/2=2-2A3,A3=1/4
以此类推,A4=1/8,A5=1/16,...An=1/2^(n-1)
Sn为等比数列,其通项为 Sn=2-2/2^n
Sn+P*n+P/2∧n=2-2/2^n+Pn+P/2^n,要使该数列为等差数列,需消去1/2^n项,即 P=2,此时该数列为 2+2n,是等差数列