a(n+1)+x*2^(n+1)=3an+2^n+x*2^(n+1)a(n+1)+x*2^(n+1)=3an+(2x+1)*2^na(n+1)+x*2^(n+1)=3[an+(2x+1)/3*2^n]令x=(2x+1)/3x=1所以a(n+1)+2^(n+1)=3(an+2^n)[a(n+1)+2^(n+1)]/(an+2^n)=3an+2^n是等比数列,q=3an+2^n=(a1...