化简:当n=1/2时,求(3n-1)(n+1)+(2n-1)(n-1)的值.
化简:当n=1/2时,求(3n-1)(n+1)+(2n-1)(n-1)的值.
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,
若n²+3n=1,求n(n+1)(n+2)+1的值.
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
证明不等式:(1/n)^n+(2/n)^n+(3/n)^n+.+(n/n)^n
求1/n+1 +1/n+3 +...1/n+2n+1 当n趋向无穷大时的极限
lim[1/(n+1)+1/(n+2)+1/(n+3)+、、、1/(n+n)]当n趋于无穷大时的极限?
[3n(n+1)+n(n+1)(2n+1)]/6+n(n+2)化简
当n为正偶数,求证n/(n-1)+n(n-2)/(n-1)(n-3)+...+n(n-2).2/(n-1)(n-3)..
(1/(n^2 n 1 ) 2/(n^2 n 2) 3/(n^2 n 3) ……n/(n^2 n n)) 当N越于无穷大
化简(n+1)(n+2)(n+3)
2^n/n*(n+1)