数列{an}是等差数列,a1=-2,a3=2 求"若bn=2的an次方,求数列{an*bn}的前n项和Sn.

数列{an}是等差数列,a1=-2,a3=2 求"若bn=2的an次方,求数列{an*bn}的前n项和Sn.
数列{an}是等差数列,a1=-2,a3=2 求"若bn=2的an次方,求数列{an*bn}的前n项和Sn.

数列{an}是等差数列,a1=-2,a3=2 求"若bn=2的an次方,求数列{an*bn}的前n项和Sn.
由题意很容易求到an=2n-4;bn=2^2n-4,an是等差数列bn是等此数列,等差乘等比用错位相减法用4Sn-Sn