1/2+1/6+1/12+.+1/n(n+1)=2003/2004 求n
1\n(n+3)+1\(n+3)(n+6)+1\(n+6)(n+9)=1\2 n+18 n为正整数,求n的值
Sn=n(n+2)(n+4)的分项等于1/6[n(n+2)(n+4)(n+5)-(n-1)n(n+2)(n+4)]吗?
若3n^2-n=1,求6n^3+7n^2-5n+2003的值
2^n/n*(n+1)
(n+1)^n-(n-1)^n=?
证明不等式:(1/n)^n+(2/n)^n+(3/n)^n+.+(n/n)^n
[3n(n+1)+n(n+1)(2n+1)]/6+n(n+2)化简
若n²+3n=1,求n(n+1)(n+2)+1的值.
3n²-n=1 求6n³+7n²-5n+2014
1、若f(n)=[n²+1]-n,g(n)=n-[n²-1],h(n)=1/(2n),求f(n),g
lim[n/(n*n+1*1)+n/(n*n+2*2)+...+n/(n*n+n*n)],当x趋向无穷大时,怎么求极限,
求极限Xn=n/(n^2+1)+n/(n^2+2)+n/(n^2+3)+……+n/(n^2+n),