Cn=3n+3/n-n^2/2^(n+1)-1/2^(n+1)
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¬å¼å¾n(3n+3)/2
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¬å¼ä¸ºSn=1+1/2+1/3+â¦+1/n=ln(n)+Cï¼(C为欧æ常æ°)
3/næ±å为3ln(n)+3C
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¬å¼ä¸ºå¾-1/4*(1-1/2^n)/(1-1/2)
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Sn= 1^2/2^2+2^2/2^3+3^2/2^4+.....+(n-1)^2/2^n+n^2/2^(n+1)
2Sn=1^2/2^1+2^2/2^2+3^2/2^3+4^2/2^4+.... +n^2/2^n
Sn=1^2/2^1+(2*1+1)/2^2+(2*2+1)/2^3+(2*3+1)/2^4+.... +(2*(n-1)+1)/2^n-n^2/2^(n+1)
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Sn= 1^2/2^1+(2*1+1)/2^2+(2*2+1)/2^3+(2*3+1)/2^4+.... +(2*(n-1)+1)/2^n-n^2/2^(n+1)
2Sn=1^2+(2*1+1)/2^1+(2*2+1)/2^2+(2*3+1)/2^3+.... +(2*(n-1)+1)/2^(n-1)-n^2/2^n
Sn=1^2+2/2^1+2/2^2+2/2^3+.... +2/2^(n-1)-n^2/2^n+n^2/2^(n+1)
=1+1*(1-1/2^(n-1))/(1-1/2)+n^2/2^(n+1)
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Tn=n(3n+3)/2+3ln(n)+3C-(1+1*(1-1/2^(n-1))/(1-1/2)+n^2/2^(n+1))-1/4*(1-1/2^n)/(1-1/2)
=3n(n+1)/2+3lnn+3C-7/2-(n^2-1)/2^(n+1)
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