n(n+1)+(n-1)n+……+1*2=(1/6)n(n+1)(n+2)的推导过程,
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?
2^n/n*(n+1)
证明不等式:(1/n)^n+(2/n)^n+(3/n)^n+.+(n/n)^n
(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
证明不等式:(1/n)的n次方+(2/n)的n次方+……+(n/n)的n次方
[3n(n+1)+n(n+1)(2n+1)]/6+n(n+2)化简
(n+1)^n-(n-1)^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
数学不等式证明题n=1,2,……证明:(1/n)^n+(1/2)^n+……+(n/n)^n第二个是(2/n)^n
数学归纳法证明:1*n+2(n-1)+3(n-2)+…+(n-1)*2+n*1=(1/6)n(n+1)(n+2)
用数学归纳法证明:1*n+2(n-1)+3(n-2)+…+(n-1)*2+n*1=(1/6)n(n+1)(n+2)
求极限Xn=n/(n^2+1)+n/(n^2+2)+n/(n^2+3)+……+n/(n^2+n),