已知{an}的通项an=(2n-3)*4^n-2 求数列{an}的前n项和Sn
问题描述：
已知{an}的通项an=(2n-3)*4^n-2 求数列{an}的前n项和Sn
答
a1 = -1 * 4^(-1)a2 = 1 * 4^0a3 = 3 * 4^1a4 = 5 * 4^2.an = (2n - 3) * 4^(n - 2)Sn = a1 + a2 + a3 + a4 + a5 +.+ (2n - 3) * 4^(n - 2)Sn = -1 * 4^(-1) + 1 * 4^0 + 3 * 4^1 + 5 * 4^2+.+ (2n - 3) * 4^(n - 2)...