化简:+2×2!+3×3!+……+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
[3n(n+1)+n(n+1)(2n+1)]/6+n(n+2)化简
化简(n+1)(n+2)(n+3)
求极限Xn=n/(n^2+1)+n/(n^2+2)+n/(n^2+3)+……+n/(n^2+n),
用数学归纳法证明:1×2×3+2×3×4+…+n×(n+1)×(n+2)=n(n+1)(n+2)(n+3)4(n∈N
VB编程n!+(n+1)!+(n+2)!+(n+3)!+……+(n+m)!
证明1/(n+1)+1/(n+2)+1/(n+3)+……+1/(n+n)
lim(1/n^2+4/n^2+7/n^2+…+3n-1/n^2)
计算:C(1,n)+2C(2,n)+3C(3,n) + … + nC(n,n)
证明不等式:(1/n)^n+(2/n)^n+(3/n)^n+.+(n/n)^n
化简:4n+3×4n-1+32×4n-2+…+3n-1×4+3n.
化简:1/(n+1)(n+2)+1/(n+2)(n+3)+1/(n+3)(n+4)