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a(n+1)=[(n+1)/n]an+(n+1)/2^n两边同除(n+1)得:a(n+1)/(n+1)=an/n+1/2^n这步不懂?b1=a1/1=1b(n+1)-bn=1/2^n还有这步不懂?
题目详情
a(n+1)=[(n+1)/n]an+(n+1)/2^n
两边同除(n+1)得:a(n+1)/(n+1)=an/n+1/2^n这步不懂?
b1=a1/1=1
b(n+1)-bn=1/2^n还有这步不懂?
两边同除(n+1)得:a(n+1)/(n+1)=an/n+1/2^n这步不懂?
b1=a1/1=1
b(n+1)-bn=1/2^n还有这步不懂?
▼优质解答
答案和解析
a(n+1)=[(n+1)/n]an+(n+1)/2^n,
a(n+1)/(n+1)=[(n+1)/n]*1/(n+1)*an+(n+1)/2^n*1/(n+1),
约分(n+1)得:
a(n+1)/(n+1)=an/n+1/2^n.
令bn=an/n,则b(n+1)=a(n+1)/(n+1).
故
b1=a1/1=1,
b(n+1)-bn=1/2^n
a(n+1)/(n+1)=[(n+1)/n]*1/(n+1)*an+(n+1)/2^n*1/(n+1),
约分(n+1)得:
a(n+1)/(n+1)=an/n+1/2^n.
令bn=an/n,则b(n+1)=a(n+1)/(n+1).
故
b1=a1/1=1,
b(n+1)-bn=1/2^n
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