1/1×3+1/3×5+1/5×7+···+1/(2n-1)(2n+1)
已知888个连续正整数之和:n+(n+1)+(n+2)+(n+3)+(n+4)+(n+5)+(n+6)+(n+7)+··
证明不等式:(1/n)^n+(2/n)^n+(3/n)^n+.+(n/n)^n
证明(1+2/n)^n>5-2/n(n属于N+,n>=3)
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+3+5+7+9+···+(2n-5)+(2n-3)+(2n-1)+(2n+1)
一道数列求和题1/2n+3/4n+5/8n+...+(2n-1)/n*2^n
[3n(n+1)+n(n+1)(2n+1)]/6+n(n+2)化简
证明:(2n!)/2^n*n!=1*3*5···(2n-1)
化简(n+1)(n+2)(n+3)
lim 9^n+4^n+2/5^n-3^2n-1 n趋于无穷大时
2^n/n*(n+1)
lim[n/(n^2+1^2)+n/(n2+2^2)+···n/(n^2+n^2)] n->无穷大