1/1x2+1/2x3+1/3x4+……+1/9x1o= 1/1x2-1/2x3-1/3x4……-
问题描述：
1/1x2+1/2x3+1/3x4+……+1/9x1o= 1/1x2-1/2x3-1/3x4……-
1/1x2+1/2x3+1/3x4+……+1/9x1o=
1/1x2-1/2x3-1/3x4……-1/9x10=
答
=1-1/2+1/2-1/3+1/3-1/4+……+1/9-1/10
=1-1/10
=9/10那请问减法的呢？。。。。忘了，等下啊，我在写忘了，等下啊，我在写好吧1-1/1*2-1/2*3-1/3*4-……-1/9*10
=1-(1-/2)-(1/2-1/3)-(1/3-1/4)-……-(1/9-1/10)
=1-1+1/2-1/2+1/3-1/3+1/4-……-1/9+1/10
=1/10