图片插不成功- =求lim{3/(1^2*2^2)+5/(2^2乘以3^2)+……+(2n+1)/n^2*(n+1)^2}
人气:436 ℃ 时间:2020-01-28 03:37:44
解答
题呢?有了。。lim(n→∞){3/(1^2*2^2)+5/(2^2×3^2)+……+(2n+1)/n^2*(n+1)^2}=lim(n→∞){(2²-1²)/(1^2*2^2)+(3²-2²)/(2^2×3^2)+……+((n+1)²-n²)/(n^2*(n+1)^2)}=lim(n→∞){1-1/2²+1/2²-1/3²+……+1/n²-1/(n+1)²}=lim(n→∞){1-1/(n+1)²)=1
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