初中数学问题(1-1/2+1/3-1/
40应为49
设分子=a，分母=b
a-b=(1-1/2+1/3-1/4+1/5-1/6+。。。。。。-1/24+1/25)-2/26-2/28-2/30-。。。。。。-2/50
=(1-1/2+1/3-1/4+1/5-1/6+。 。。。。。-1/24+1/25)-(1/13+1/14+1/15+。。。。。。+1/25)
=(1-1/2+1/3-1/4+1/5-1/6+。。。。。。-1/12)-2/14-2/16-2/18-。 。。。。。-2/24
=(1-1/2+1/3-1/4+1/5-1/6+。。。。。。 -1/12)-(1/7+1/8+1/9+1/10+1/11+1/12)
=...全部
40应为49
设分子=a，分母=b
a-b=(1-1/2+1/3-1/4+1/5-1/6+。。。。。。-1/24+1/25)-2/26-2/28-2/30-。。。。。。-2/50
=(1-1/2+1/3-1/4+1/5-1/6+。
。。。。。-1/24+1/25)-(1/13+1/14+1/15+。。。。。。+1/25)
=(1-1/2+1/3-1/4+1/5-1/6+。。。。。。-1/12)-2/14-2/16-2/18-。
。。。。。-2/24
=(1-1/2+1/3-1/4+1/5-1/6+。。。。。。
-1/12)-(1/7+1/8+1/9+1/10+1/11+1/12)
=(1-1/2+1/3-1/4+1/5-1/6)-(2/8+2/10+2/12)
=(1-1/2+1/3-1/4+1/5-1/6)-(1/4+1/5+1/6)
=1-1/2+1/3-1/4-1/6-1/4-1/6
=1-1/2+1/3-1/2-1/3
=0
所以a=b
a/b=1。收起
