(-3)^(n+2)+(-3)^(n+1)+2+(-3)^n*2=-214求n,解方程,
方程2分之n(n-3)=20 求n
证明不等式:(1/n)^n+(2/n)^n+(3/n)^n+.+(n/n)^n
若n²+3n=1,求n(n+1)(n+2)+1的值.
求极限Xn=n/(n^2+1)+n/(n^2+2)+n/(n^2+3)+……+n/(n^2+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
1 + (n + 1) + n*(n + 1) + n*n + (n + 1) + 1 = 2n^2 + 3n + 3
证明(1+2/n)^n>5-2/n(n属于N+,n>=3)
数列a(n)=n (n+1)(n+2)(n+3), 求S(n)怎么用高中数列原理解答?
[3n(n+1)+n(n+1)(2n+1)]/6+n(n+2)化简
化简(n+1)(n+2)(n+3)
解一个方程,950n+(1/2)n(n-1)乘(-100)=5000求n
求极限 lim(n->无穷)[(3n^2-2)/(3n^2+4)]^[n(n+1)]