1x2=(1/3)(1x2x3-0x1x2) 3x4=(1/3)(3x4x5-2x3x4) 问1x2x3+2x3x4+.+n(n+1)(n+2)=___________

问题描述:

1x2=(1/3)(1x2x3-0x1x2) 3x4=(1/3)(3x4x5-2x3x4) 问1x2x3+2x3x4+.+n(n+1)(n+2)=___________

n(n+1)(n+2)(n+3)/4