Yoem 2007-9-9 18:01
请教预备数学题
[img]http://www.freep.cn/p.aspx?u=v20__p_0709091800396375_0.jpg[/img]
红色为运算符号
:)
谢谢啦~.
echooooo 2007-9-9 18:48
原式=7-6+5-4+3-2+1+5/(2*3)-7/(3*4)+9/(4*5)-11/(5*6)+13/(6*7)-15/(7*8)+17/(8*9)
=4+(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)
=4+1/2+1/9
=4又11/18.