Toán A= 1/9.10 – 1/8.9 – 1/7.8 – ……..- 1/1.2 25/07/2021 By Emery A= 1/9.10 – 1/8.9 – 1/7.8 – ……..- 1/1.2
A=1/9.10-1/8.9-1/7.8-…-1/1.2 = 1/9-1/10-(1/1-1/2+1/2-1/3+…+1/8-1/9) = 1/9-1/10-(1-1/19) = 1/9-1/10-1+1/9 = 79/9 đây nha bn. Trả lời
A=1/9.10-1/8.9-1/7.8-…-1/1.2
= 1/9-1/10-(1/1-1/2+1/2-1/3+…+1/8-1/9)
= 1/9-1/10-(1-1/19)
= 1/9-1/10-1+1/9
= 79/9
đây nha bn.