来自马晓岩的问题
1/2+1/6+1/12+1/20+1/30+1/42+1/56+1/72=(1+1/2+1/3+1/4+1/5)×(1/2+1/3+1/4+1/5+1/6)-(1+1/2+1/3+1/4+1/5+1/6)×(1/2+1/3+1/4+1/5)
1/2+1/6+1/12+1/20+1/30+1/42+1/56+1/72=
(1+1/2+1/3+1/4+1/5)×(1/2+1/3+1/4+1/5+1/6)-(1+1/2+1/3+1/4+1/5+1/6)×(1/2+1/3+1/4+1/5)
1回答
2020-09-25 20:00