S=3/1.4+3/4.7+3/7.10+........+3/40.43+3/43.46. A=1/1.4+1/4.7+1/7.10+1/13.16+1/16.19+1/19.22 B=1/6+1/12+1/20+1/30+1/42+1/56+........1/10 hlep me !

Các câu hỏi liên quan