(3²+1²)/(3²-1²)+(5²+1)/(5²-1)+(7²+1)/7²-1)+……+(1995²+1)/(1995²-1)=
问题描述:
(3²+1²)/(3²-1²)+(5²+1)/(5²-1)+(7²+1)/7²-1)+……+(1995²+1)/(1995²-1)=
答
(3²+1²)/(3²-1²)=1+2/[2×4]=1+(4-2)/[2×4]1+1/2-1/4
(5²+1)/(5²-1)=1+2/(5²-1)=1+(6-4)/[4×6]=1+1/4-1/6
.
(1995²+1)/(1995²-1)=1+(1996-1994)/[1994×1996]=1+1/1994-1/1996
(3²+1²)/(3²-1²)+(5²+1)/(5²-1)+(7²+1)/7²-1)+……+(1995²+1)/(1995²-1)
=997+1/2-1/1996
=997又997/1996