已知等差数列an,a1=10,d=2,数列an满足bn=(n/2)an-6n,n∈N*
问题描述:
已知等差数列an,a1=10,d=2,数列an满足bn=(n/2)an-6n,n∈N*
求数列an与bn的通向公式
答
答:
等差数列An,A1=10,d=2
An=A1+(n-1)d=10+2(n-1)=2n+8
Bn=(n/2)An-6n
=(n/2)*(2n+8)-6n
=n^2+4n-6n
=n^2-2n
所以:
An=2n+8
Bn=n^2-2n