Question

数学问题，求详细过程！

1/2+1/6+1/12+1/20+1/30+1/42+1/56+1/72

Answer 1

1/2+1/6+1/12+1/20+1/30+1/42+1/56+1/72
=1/1*2+1/2*3+1/3*4+1/4*5+1/5*6+1/6*7+1/7*8+1/8*9
=1-1/2+1/2-1/3+1/3-1/4+1/4-1/5+1/5-1/6+1/6-1/7+1/7-1/8+1/8-1/9
=1-1/9
=8/9

Answer 2

你的上式=1/(1*2)+1/(2*3)+1/(3*4)+、、、1/(7*8)+1/(8*9)
=1/1-1/2+1/2-1/3+1/4-1/5+、、、+1/7-1/8+1/8-1/9
到这里该消去的消去 最后得到
=1-1/9
=8/9
不会看不懂吧 呵呵 希望对你有帮助