求证:(1*3*……(2n-1))/(2*4……(2n))
求证1×2+2×3+3×4+…+n(n+1)=13n(n+1)(n+2)
求证Cn0Cn1+Cn1Cn2+……+Cn(n-1)Cnn=(2n)!/(n-1)!(n+1)!
求证1!+2*2!+3*3!+…+n*n!=(n+1)!-1
求证:1²+2²+3²+……+n²=[n(n+1)(n+2)]/6
求证:1*2+2*5+3*8+…+n(3n-1)=n^2(n+1)
若n为自然数且n +1|1×2×3×…×n+ 1.求证:n +1是个质数
求证1²+2²+3²+……+n²=(1/6*n(n+1)(2n+1))/n(n为
求证:(1*3*……(2n-1))/(2*4……(2n))
求证:ln2/2+……lnn/n<n^2/2(2n+1)
(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
用数学归纳法证明:1×2×3+2×3×4+…+n×(n+1)×(n+2)=n(n+1)(n+2)(n+3)4(n∈N
lim(1/n^2+4/n^2+7/n^2+…+3n-1/n^2)