+2*2!+3*3!+4*4!……n*n!
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)
如果,n是大于2的整数,计算1/(n-1)(n-2)+1/(n-2)(n-3)+1/(n-3)(n-4)+……+1/(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
(n-1)(n-2)(n-3)(n-4)……(n-m+1)(n-m)n大于m 的计算公式
C(n.0)+2C(n.1)+4C(n.2)+C(n.2)+C(n.3)…+C(n.n)=?
求和4^n+3×4^(n-1)+3^2×4(n-2)+……+3^(n-1)×4+3^n
化简:4n+3×4n-1+32×4n-2+…+3n-1×4+3n.
求极限lim(1/2n+3/4n+……+(2^n-1)/(2^n*n))
用数学归纳法证明等式1+2+3+…+(n+3)=(n+3)(n+4)2(n∈N
求证1×2+2×3+3×4+…+n(n+1)=13n(n+1)(n+2)
简便方法计算:1/n+1+1/n+2+1/n+3+1/n+4+…+1/n+100