设定数列{an}的前n项和为Sn,现在已知此数列满足an+Sn=10-7/2^n,那么an的通项公式是____。 2^n/4 + 4 -0.75n + 4 (2.5n+3)/ 2^n (3n+2)/ 2^n (3.5n+3)/ 2^n -5/2^n + 4
2^n/4 + 4
-0.75n + 4
(2.5n+3)/ 2^n
(3n+2)/ 2^n
(3.5n+3)/ 2^n
-5/2^n + 4