规定X@y=Xx(X+1)x(X+2)x.x(X+y-1),如2@4=2x3x4x5已知n+1/n@3=1/575,求自然数n
问题描述:
规定X@y=Xx(X+1)x(X+2)x.x(X+y-1),如2@4=2x3x4x5已知n+1/n@3=1/575,求自然数n
答
题目是这样的:(n+1)/【n@3】=(n+1) /【 n *(n+1)*(n+2)】=1/575
所以575*(n+1)=n *(n+1)*(n+2)
化简得n^3+3n^2-573n-575=0
解得n=23