1/3+2/8+2/15+2/24+2/35+2/48+2/63+2/80

问题描述:

1/3+2/8+2/15+2/24+2/35+2/48+2/63+2/80

嗯,原式=2(1/8+1/24+1/48+1/80)+2(1/15+1/35+1/63)+1/3 =2[1/(2*4)+1/(4*6)+1/(6*8)+1/(8*10)]+2[1/(3*5)+1/(5*7)+1/(7*9)]+1/3 =[1/2-1/4+1/4-1/6+1/6-1/8+1/8-1/10]+[1/3-1/...