(4^n-1)/(4-1)+(1-1/4^n)/(1-1/4)+2n怎么化简?
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?
化简:1/(n+1)(n+2)+1/(n+2)(n+3)+1/(n+3)(n+4)
(n+1)(n+2)/1 +(n+2)(n+3)/1 +(n+3)(n+4)/1
证明:1+2C(n,1)+4C(n,2)+...+2^nC(n,n)=3^n .(n∈N+)
若n为正整数,求1/n(n+1)+1/(n+1)(n+2)+1/(n+2)(n+3)+1/(n+3)(n+4)+.+1/
用数学归纳法证明:1×2×3+2×3×4+…+n×(n+1)×(n+2)=n(n+1)(n+2)(n+3)4(n∈N
lim(1/n^2+4/n^2+7/n^2+…+3n-1/n^2)
求lim(n+1)(n+2)(n+3)/(n^4+n^2+1)
求极限 lim(n->无穷)[(3n^2-2)/(3n^2+4)]^[n(n+1)]
一道极限题,lim[n^2(2n+1)]/(n^3+n+4)n->∞
lim 9^n+4^n+2/5^n-3^2n-1 n趋于无穷大时
根号【(2n+1)/(n²+n)】平方-4/(n平方+n )化简