化简4n^3-6n^2-2n+3
[3n(n+1)+n(n+1)(2n+1)]/6+n(n+2)化简
化简:1/(n+1)(n+2)+1/(n+2)(n+3)+1/(n+3)(n+4)
证明不等式:(1/n)^n+(2/n)^n+(3/n)^n+.+(n/n)^n
化简(n+1)(n+2)(n+3)
如果正整数n使得[n/2]+[n/3]+[n/4]+[n/5]+[n/6]=69,则n=
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
16n^a+4n^3+6n^2+7^n=0,求n
(m-n)2(n-m)3(n-m)4化简
(n+1)(n+2)/1 +(n+2)(n+3)/1 +(n+3)(n+4)/1
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(1*3*4+2*6*8……n*3n*4n)/(1*3*5+2*8*10+……n*4n*5n)