1*3/1+3*5/1+5*7/1+……+(2n-1)(2n+1)/1=?
证明(1+2/n)^n>5-2/n(n属于N+,n>=3)
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
lim(1/n^2+4/n^2+7/n^2+…+3n-1/n^2)
求极限Xn=n/(n^2+1)+n/(n^2+2)+n/(n^2+3)+……+n/(n^2+n),
已知Sn=2+5n+8n^2+…+(3n-1)n^n-1(n∈N*)求Sn
用数学归纳法证明“(n+1)(n+2)…(n+n)=2^n·1·3·5…(2n-1)(n∈N*)”时,从n=k到n=k+
1 + (n + 1) + n*(n + 1) + n*n + (n + 1) + 1 = 2n^2 + 3n + 3
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?
用数学归纳法证明:(n+1)+(n+2)+…+(n+n)=n(3n+1)2
[3n(n+1)+n(n+1)(2n+1)]/6+n(n+2)化简
f(n)=1/(n+1)+1/(n+2)+1/(n+3)……+1/2n (n∈N*),f(n+1