简便计算:分数连加 (备注:/=分之 1/6=六分之一) 1/(2*3)+1/(3*4)+1/(4*5)+1/(5*6)+1/(6*7)+

问题描述:

简便计算:分数连加 (备注:/=分之 1/6=六分之一) 1/(2*3)+1/(3*4)+1/(4*5)+1/(5*6)+1/(6*7)+
1/(2*3)+1/(3*4)+1/(4*5)+1/(5*6)+1/(6*7)+1/(7*8)

1/(2*3)+1/(3*4)+1/(4*5)+1/(5*6)+1/(6*7)+1/(7*8)
=1/2-1/3+1/3-1/4+1/4-1/5+1/5-1/6+1/6-1/7+1/7-1/8
=1/2-1/8
=4/8-1/8
=3/8