2^n+1-2^n=?4×5^n-5^n+1=?
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?
证明(1+2/n)^n>5-2/n(n属于N+,n>=3)
2^n+1-2^n=?4×5^n-5^n+1=?
求极限 lim(n→∞)[根号(n^2+4n+5)-(n-1)] =
M=(N-1)×1+(N-2)×2+(N-3)×4+(N-4)×8+(N-5)×16+(N-6)×32+(N-7)×64
证明:1+2C(n,1)+4C(n,2)+...+2^nC(n,n)=3^n .(n∈N+)
如果正整数n使得[n/2]+[n/3]+[n/4]+[n/5]+[n/6]=69,则n=
阶乘(2n-1)!=(2n)!/(2^n*n!
1 + (n + 1) + n*(n + 1) + n*n + (n + 1) + 1 = 2n^2 + 3n + 3
如果正整数n使得[n/2]+[n/3]+[n/4]+[n/5]+[n/6]=69,则n为( ).([ n ]表示不超过n
lim 9^n+4^n+2/5^n-3^2n-1 n趋于无穷大时
2^n/n*(n+1)