1×1+2×2+3×3+---+n×n=n(n+1)(2n+1)\/6
来源：学生作业帮助网 编辑：六六作业网 时间：2024/11/09 10:40:56
1×1+2×2+3×3+---+n×n=n(n+1)(2n+1)\/61×1+2×2+3×3+---+n×n=n(n+1)(2n+1)\/61×1+2×2+3×3+---+n×n=n(n+1)(2n+
1×1+2×2+3×3+---+n×n=n(n+1)(2n+1)\/6
1×1+2×2+3×3+---+n×n=n(n+1)(2n+1)\/6
1×1+2×2+3×3+---+n×n=n(n+1)(2n+1)\/6
2+3×3+---+n×n=n(n+1)(2
2+3×3+---+n×n=n(n+1)(2
证明不等式：(1/n)^n+(2/n)^n+(3/n)^n+.+(n/n)^n
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
高数题：n趋近于0,lim｛1/（n^2+n+1)+2/(n^2+n+2)+3/(n^2+n+3)+.+n/(n^2+n+n)｝=?
为什么:n×(n+1)=1/3[n(n+1)×(n+2)-(n-1)×n×(n+1)]
为什么n(n+1)(n+2)(n+3)=(n²+3n+2)(n²+3n)?
数列a(n)=n (n+1)(n+2)(n+3),求S(n)
n+(n+1)+(n+2)+(n+3)+(n+4)=5n+10这道题怎么解
n(n-1)(n-2)（n-3)（n-4)=154440.求N值 要步骤
[3n(n+1)+n(n+1)(2n+1)]/6+n(n+2)化简
[3n(n+1)+n(n+1)(2n+1)]/6+n(n+2)化简
化简n分之n-1+n分之n-2+n分之n-3+.+n分之1
化简n分之n-1+n分之n-2+n分之n-3+.+n分之1
1*N+2*（N-1）+3*（N-2）+...+N*1=1/6N(N+1)(N+2)
用数学归纳法证明：(n+1)(n+2)(n+3)+.+(n+n)=(2^n)*1*3*.(2n-1)
证明：1+2C(n,1)+4C(n,2)+...+2^nC(n,n)=3^n .(n∈N+)
e^(1/n)+e^(2/n)+e^(3/n)+…+e^(n-1/n)+e^(n/n)=?
化简(n+1)(n+2)(n+3)
设f(n)=1/n+1+1/n+2+1/n+3+……+1/3n(n∈N+),则f(n+1)-f(n)=?