分式计算1/(1*2)+1/(2
1/(1*2)=1-1/2
1/(2*3)=1/2-1/3
1/(3*4)=1/3-1/4
+···+
1/(9*10)=1/9-1/10
左边 加 左边就是题目 = 右边+右边
1/(1*2)+1/(2*3)+1/(3*4)+···+1/(9*10)=
1-1/2+1/2-1/3+1/3-1/4+1/4-1/5+。 。。+1/9-1/10
=1-1/10
=9/10 。
1/(1*2)=1-1/2
1/(2*3)=1/2-1/3
1/(3*4)=1/3-1/4
+···+
1/(9*10)=1/9-1/10
左边 加 左边就是题目 = 右边+右边
1/(1*2)+1/(2*3)+1/(3*4)+···+1/(9*10)=
1-1/2+1/2-1/3+1/3-1/4+1/4-1/5+。
。。+1/9-1/10
=1-1/10
=9/10 。收起