(1/2+1/4+1/6+1/8)-(1/3+1/6+1/9+1/12)+(1/4+1/8+1/12+1/16)-(1/5+1/10+1/15+1/20)=

问题描述:

(1/2+1/4+1/6+1/8)-(1/3+1/6+1/9+1/12)+(1/4+1/8+1/12+1/16)-(1/5+1/10+1/15+1/20)=

楼主您好:(1/2+1/4+1/6+1/8)-(1/3+1/6+1/9+1/12)+(1/4+1/8+1/12+1/16)-(1/5+1/10+1/15+1/20)=1/2(1+1/2+1/3+1/4)-1/3(1+1/2+1/3+1/4)+1/4(1+1/2+1/3+1/4)-1/5(1+1/2+1/3+1/4)=(1+1/2+1/3+1/4)(1/2-1/3+1/4-...