高一数学在线急..已知数列{an}满足a1=1,a(n+1)-2an=2^n,求an
1,已知数列{an}满足a1=1,a(n+1)-2an=2^n,求an
2,已知数列{an}满足a(n+1)=2an-3,求an
3,求数列2-1,2^2-2,2^3-3,...,2^n-n,的前n项和
三道题求过程,分不多了...