求证:1/2^3 +1/3^3 +1/4^3 +……+1/(n+1)^3
求证1×2+2×3+3×4+…+n(n+1)=13n(n+1)(n+2)
求证1!+2*2!+3*3!+…+n*n!=(n+1)!-1
求证:3/2-1/n+1
求证1/(n+1)+1/(n+2)+.+1/(3n+1)>1 [n属于N*]
求证:(1*3*……(2n-1))/(2*4……(2n))
求证:C0n+2C1n+3C2n+…+(n+1)Cnn
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)..
求证:1*2+2*5+3*8+…+n(3n-1)=n^2(n+1)
求证:1²+2²+3²+……+n²=[n(n+1)(n+2)]/6
若n为自然数且n +1|1×2×3×…×n+ 1.求证:n +1是个质数
求证1+1/2+1/3+...+1/n>In(n+1) (n属于N+)
求证不等式(3^n-4^n)大于等于4^(n-1)其中n属于正整数