1+3+5+7+9+11+13+15+…+(2n-1)=?
证明(1+2/n)^n>5-2/n(n属于N+,n>=3)
1+3+5+7+9+.+(2n-1)+(2n+1)+(2n+3)=
已知Sn=2+5n+8n^2+…+(3n-1)n^n-1(n∈N*)求Sn
M=(N-1)×1+(N-2)×2+(N-3)×4+(N-4)×8+(N-5)×16+(N-6)×32+(N-7)×64
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+
n为正整数,3+5+7+9+.(2n+1)=168,则n=
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),
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
若3n^2-n=1,求6n^3+7n^2-5n+2003的值
lim 9^n+4^n+2/5^n-3^2n-1 n趋于无穷大时
3n²-n=1 求6n³+7n²-5n+2014