Question

2*2/1*3+4*4/3*5+6*6/5*7+8*8/7*9+10*10/9*11

Answer 1

(2*2)/(1*3)=1+1/(1*3)=1+(1/1-1/3)/2
(4*4)/(3*5)=1+1/(3*5)=1+(1/3-1/5)/2
(6*6)/(5*7)=1+1/(5*7)=1+(1/5-1/7)/2
(8*8)/(7*9)=1+1/(7*9)=1+(1/7-1/9)/2
(10*10)/(9*11)=1+1/(9*11)=1+(1/9-1/11)/2

总的=1+1+1+1+1 +1/(1*3)+1/(3*5)+1/(5*7)+1/(9*11)
=5+(1/1-1/3 +1/3-1/5 +1/5-1/7 +1/7-1/9 +1/9-1/11)/2
=5+(1-1/11)/2
=5+5/11

字有点小，不好意思
看起来可可能有点费劲。不过应该详细了
给个好评吧。