已知An=2A(n-1)+2^n-1(n≥2)a1=5 a2=13 a3=33 a4=81.{(An+α)/2^n}为等差数列,求a
问题描述:
已知An=2A(n-1)+2^n-1(n≥2)a1=5 a2=13 a3=33 a4=81.{(An+α)/2^n}为等差数列,求a
答
An=2A(n-1)+2^n-1 等式两边同时除以2^n可得 An/2^n=A(n-1)/2^(n-1)-1/2^n+1 ……①{(An+α)/2^n}为等差数列,所以(An+α)/2^n=(A(n-1)+α)/2^(n-1)+d (d为参数)整理得An/2^n=A(n-1)+α/2^n+d ……②对...