更新时间2018-07-06 19:18:30
1/(2*4)+1/(4*6)+1/(6*8)+...+1/(48*50)
=1/2*[2/(2*4)+2/(4*6)+2/(6*8)+...+2/(48*50)]
=1/2*(1/2-1/4+1/4-1/6+1/6-1/8+...+1/48-1/50)
=1/2*(1/2-1/50)
=1/2*24/50
=6/25
2乘4分之一加4乘6分之一加6乘8分之一,一直加到48乘50分之一
1/(2*4)+1/(4*6)+1/(6*8)+...+1/(48*50)
=1/2*[2/(2*4)+2/(4*6)+2/(6*8)+...+2/(48*50)]
=1/2*(1/2-1/4+1/4-1/6+1/6-1/8+...+1/48-1/50)
=1/2*(1/2-1/50)
=1/2*24/50
=6/25
应该是=34吧
答案等于34