3/1+15/1+35/1+63/1···+(2N+1)(2N+3)/1+···+8099/1
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)+··
lim[n/(n^2+1^2)+n/(n2+2^2)+···n/(n^2+n^2)] n->无穷大
证明不等式:(1/n)^n+(2/n)^n+(3/n)^n+.+(n/n)^n
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+
用数学归纳法证明 (n+1)(n+2)…(n+n)=2^n·1·3·……·(2n-1)(n∈N*),从假定当n=k时公式
1+3+5+7+9+···+(2n-5)+(2n-3)+(2n-1)+(2n+1)
证明:(2n!)/2^n*n!=1*3*5···(2n-1)
求幂级数∑(n=1,∞) x^n/n·3^n的收敛域
[3n(n+1)+n(n+1)(2n+1)]/6+n(n+2)化简
六个共面共点力大小分别是1N,2N,2N,3N,4N,5N,和6N,相互之间的夹角均为60·,则他们合力的大小为多少N!
n是自然数,当n趋于无穷大时,求[n·tan(1/n)]^(n^2)的极限
化简(n+1)(n+2)(n+3)