化简:√( 1 +1/n^2 + 1/(n+1)^2 ) -1
2^n/n*(n+1)
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
化简(n+1)(n+2)(n+3)
化简[n^2+(n+1)^2]/n(n+1) 化简额
化简:1/(n+1)(n+2)+1/(n+2)(n+3)+1/(n+3)(n+4)
n(n+1)(n+2)数列求和
n(n+1)(n+2)等于多少?
limn→∞n√(1+1/n)(1+2/n)...(1+n/n)等于多少?
计算:n(n+1)(n+2)(n+3)+1
阶乘(2n-1)!=(2n)!/(2^n*n!
lim[(n+3)/(n+1))]^(n-2) 【n无穷大】