hoi gi vay

hinh nhu bang 96 cm vuông

đặt A = 1/ 2.3 +.....................................+1 

ta có A = ................(viết lại biểu thức ) 

A = 1/2 - 1/3 + 1/3 - 1/4 + 1/4 - 1/5 + ......+ 1/999 - 1/ 1000 + 1 

= 1/2 - 1/1000  + 1 

= 499/ 1000 + 1 

= 1499/ 1000

1/2.3 +1/3.4+...+1/999.100 +1

=1/2-1/3+1/3-1/4+...+1/999-1/100 +1

=1/2-1/100+1

=49/100+1

=149/100

(a-b-c)-(a-c)^2-2ab+2ab

=a-b-c-a^2+2ac-c^2-2ab+2ab

=a-b-c-a^2+2ab-c^2

mk thật sự k hỉu để ns j luôn đó

Ì. Mk cụg chả hỉu j cả. Cô mk ra thế đấy

Ngậm cả buổi mà cụg nỏ ra 

de vay ma khong biet

Ta có \(S=\frac{2016}{5}+\frac{2016}{10}+\frac{2016}{30}+...+\frac{2016}{47530}+\frac{2016}{48150}\)

             \(=\frac{2016}{5}.\left(\frac{1}{1}+\frac{1}{2}+\frac{1}{6}+...+\frac{1}{9506}+\frac{1}{9630}\right)\)

             \(=\frac{2016}{5}.\left(\frac{1}{1}+\frac{1}{1.2}+\frac{1}{2.3}+...+\frac{1}{97.98}+\frac{1}{98.99}\right)\)

              \(=\frac{2016}{5}.\left(\frac{1}{1}+\frac{1}{1}-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+...+\frac{1}{97}-\frac{1}{98}+\frac{1}{98}-\frac{1}{99}\right)\)

                \(=\frac{2016}{5}.\left(1+1-\frac{1}{99}\right)\)

                 \(=\frac{2016}{5}.\frac{197}{99}\)

                  \(=\frac{44128}{55}\)

(x,y)=(0,19); (19,0)