1x2=1⼀3x[1x2x3-0x1x2] 2x3=1⼀3x[2x3x4-1x2x3] 3x4=1⼀3x[3x4x5-2x3x4]yo由以上三个等式相加,可得,计算3题

2024-12-18 17:07:53
推荐回答(1个)
回答1:

【1】1x2+2x3+3x4+...+10x11
=10×11×12/3
=440
【2】1x2+2x3+3x4+...+nx[n+1]
=n(n+1)(n+2)/3
【3】请类比以上形式,尝试连续三个字然数的乘积的规律并计算
1x2x3+2x3x4+3x4x5+...+7x8x9
=7×8×9×10/4
=1260