Question

A=\(\frac{1}{1.2}+\frac{1}{2.3}+\frac{1}{3.4}+...+\frac{1}{2016.2017}\)

B=\(\frac{1}{1.3}+\frac{1}{3.5}+\frac{1}{5.7}+...+\frac{1}{2016.2017}\)

C=\(\frac{1}{2.4}+\frac{1}{4.6}+\frac{1}{6.8}+...+\frac{1}{2016.2018}\)

D=\(\frac{1}{1.2.3}+\frac{1}{2.3.4}+\frac{1}{3.4.5}+...+\frac{1}{98.99.100}\)

E=\(\frac{3}{4}.\frac{8}{9}.\frac{15}{16}\cdot...\cdot\frac{899}{900}\)

F=1.2+2.3+3.4+...+99.100

MẤY BN NÀO BIẾT THÌ GIẢI JUP MK NHA!

Answer 1

Lâm đi là: 35 phút +2 giờ 20phút =2 giờ 55 phút

Answer 2

\(A=\frac{1}{1.2}+\frac{1}{2.3}+\frac{1}{3.4}+...+\frac{1}{2016.2017}\)

\(A=1-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-\frac{1}{4}+...+\frac{1}{2016}-\frac{1}{2017}\)

\(A=1-\frac{1}{2017}\)

\(A=\frac{2016}{2017}\)

Answer 3

\(B=\frac{1}{1.3}+\frac{1}{3.5}+\frac{1}{5.7}+...+\frac{1}{2016.2018}\)

\(2B=\frac{2}{1.3}+\frac{2}{3.5}+\frac{2}{5.7}+...+\frac{2}{2016.2018}\)

\(2B=1-\frac{1}{3}+\frac{1}{3}-\frac{1}{5}+\frac{1}{5}-\frac{1}{7}+...+\frac{1}{2016}-\frac{1}{2018}\)

\(2B=1-\frac{1}{2018}\)

\(B=\frac{2017}{\frac{2018}{2}}\)

Answer 4

\(A=\frac{1}{1.2}+\frac{1}{2.3}_{ }+\frac{1}{3.4}+.....+\frac{1}{2016.2017}\)

\(=>A=\frac{1}{1}.\frac{1}{2}+\frac{1}{2}.\frac{1}{3}+\frac{1}{3}.\frac{1}{4}+...+\frac{1}{2016}.\frac{1}{2017}\)

\(=>A=\frac{1}{1}-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-\frac{1}{4}+...+\frac{1}{2016}-\frac{1}{2017}\)

\(=>A=\frac{1}{1}+\left[\frac{1}{2}-\frac{1}{2}\right]+\left[\frac{1}{3}-\frac{1}{3}\right]+\left[\frac{1}{4}-\frac{1}{4}\right]+...+\left[\frac{1}{2016}-\frac{1}{2016}\right]-\frac{1}{2017}\)

\(=>A=\frac{1}{1}-\frac{1}{2017}\)

\(=>A=\frac{2016}{2017}\)

Câu B,C.D làm tương tự

Còn cau E phân tích mảu 

Câu F .Ta phan tích thanh nhu sau rui lam tương tự:

\(E=\frac{1}{1.2}+\frac{1}{2.3}+\frac{1}{3.4}+...+\frac{1}{99.100}\)

PHẦN SAU TỰ LÀM NHA! TK MINH ĐI

Answer 5

lam di la luc 2 gio 55phut

Answer 6

bn pack_shin_hye hơi thiếu chút 

ở câu D bn phải nhân 2 và chia 2 nhé

D=\(\frac{1}{2}\left(\frac{1}{2}-\frac{1}{4}+\frac{1}{4}-\frac{1}{6}+.....+\frac{1}{2016}-\frac{1}{2018}\right).\)

D=\(\frac{1}{2}\left(\frac{1}{2}-\frac{1}{2018}\right)\)

D=...

Answer 7

A= \(\frac{1}{1}-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-\frac{1}{4}+......+\frac{1}{2016}-\frac{1}{2017}\)

A=\(1-\frac{1}{2017}\)

A= \(\frac{2016}{2017}\)

chờ mk gửi tiếp nha

Answer 8

\(A=\frac{1}{1.2}+\frac{1}{2.3}+...+\frac{1}{2016.2017}\)

    \(=\frac{1}{1}-\frac{1}{2}+...+\frac{1}{2016}-\frac{1}{2017}\)

      \(=\frac{1}{1}-\frac{1}{2017}\)

Vậy A = \(\frac{2016}{2017}\)

Answer 9

a, Lời giải

\(=\frac{1}{1}-\frac{1}{2}+...+\frac{1}{2016}-\frac{1}{2017}\)

\(=\frac{1}{1}-\frac{1}{2017}\)

\(=\frac{2016}{2017}\)

mấy phần kia tương tự