求证:1*2+2*5+3*8+…+n(3n-1)=n^2(n+1)
当n为正偶数,求证n/(n-1)+n(n-2)/(n-1)(n-3)+...+n(n-2).2/(n-1)(n-3)..
证明不等式:(1/n)^n+(2/n)^n+(3/n)^n+.+(n/n)^n
求证:1*2+2*5+3*8+…+n(3n-1)=n^2(n+1)
数学定理证明求证2^n-1=2^n-1+2^n-2+2^n-3+.+2^n-n
求证c(n,1)+2c(n,2)+3c(n,3)+...+nc(n,n)=n2^(n-1)
证明(1+2/n)^n>5-2/n(n属于N+,n>=3)
求证1/(n+1)+1/(n+2)+.+1/(3n+1)>1 [n属于N*]
(1/(n^2 n 1 ) 2/(n^2 n 2) 3/(n^2 n 3) ……n/(n^2 n n)) 当N越于无穷大
请教初一的数学题急求证:N=52*32n+1*2n-3n*3n*6n+2能被13整除.2 2n+1 n n n n+2分
1 + (n + 1) + n*(n + 1) + n*n + (n + 1) + 1 = 2n^2 + 3n + 3
求证:1+1/2+1/3+...+1/n>In(n+1)+n/2(n+1) (n属于N+)
求证1×2+2×3+3×4+…+n(n+1)=13n(n+1)(n+2)