化简:1×2×4+2×4×8+...+n×2n×4n 除以 1×4×7+2×8×14+...+n×4n×7n
计算1/(m-n)-1/(m+n)-2n/(m^2+n^2)-4n^3/(m^4+n^4)-8n^7/(m^8+n^8)
化简:1/(n+1)(n+2)+1/(n+2)(n+3)+1/(n+3)(n+4)
lim(1/n^2+4/n^2+7/n^2+…+3n-1/n^2)
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?
M=(N-1)×1+(N-2)×2+(N-3)×4+(N-4)×8+(N-5)×16+(N-6)×32+(N-7)×64
(n+1)(n+2)/1 +(n+2)(n+3)/1 +(n+3)(n+4)/1
一道数列求和题1/2n+3/4n+5/8n+...+(2n-1)/n*2^n
(2^n+4^n+6^n+8^n)^(1/n)当n趋于无穷时的极限
根号【(2n+1)/(n²+n)】平方-4/(n平方+n )化简
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:1+2C(n,1)+4C(n,2)+...+2^nC(n,n)=3^n .(n∈N+)
化简:2^4n+1-(4^2n+16^n)