化简:根号下1*5*10+2*10*20+n*5n*10n分之1*2*3+2*4*6+n*2n*3n
化简:根号下1*5*10+2*10*20+n*5n*10n分之1*2*3+2*4*6+n*2n*3n
根号(1×2×3+2×4×6+…+n×2n×3n)÷根号(1×5××10+2×10×20+…+n×5n×10n)=?
1×5×10+2×10×20+...+n×5n×10n分之1×2×3+2×4×6+...n×2n×3n
[3n(n+1)+n(n+1)(2n+1)]/6+n(n+2)化简
根号下(1*2*3+2*4*6+……+n*2n*3n)/(1*5*10+2*10*20+……+n*5n*10n)
证明不等式:(1/n)^n+(2/n)^n+(3/n)^n+.+(n/n)^n
化简(1*3*4+2*6*8……n*3n*4n)/(1*3*5+2*8*10+……n*4n*5n)
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)
证明(1+2/n)^n>5-2/n(n属于N+,n>=3)
化简(n+1)(n+2)(n+3)
计算(1×2×3+2×4×6+…+n×2n×3n)÷(1×3×5+2×6×10+…+n×3n×5n)