8-2/3-2/15-2/35-2/63-2/99-2/143-2/195-2/255=
问题描述:
8-2/3-2/15-2/35-2/63-2/99-2/143-2/195-2/255=
答
原式=8-(3-1)/(1*3)-(5-3)/(3*5)-(7-5)/(5*7)-……-(17-15)/(15*17)
=8-1+1/3-1/3+1/5-1/5+1/7-……-1/15+1/17
=7+1/17
=120/17
答
=8-(1-1/3)-(1/3-1/5)-(1/5-1/7).-(1/15-1/17)
=8-1+1/3-1/3+1/5-1/5.-1/15+1/17
=8-1+1/17=7+1/17
=120/7