A=1999/2000

B=199/200

C=511/512

hok tốt

Đáp án

mình lười trình bày cách làm lém, để đáp án thui nha

A = \(\frac{1999}{2000}\)

B = \(\frac{199}{200}\)

C = \(\frac{511}{512}\)

a)\(=\frac{1}{2}.\frac{2}{3}.\frac{3}{4}.\frac{4}{5}......\frac{99}{100}\)

\(=\frac{1.2.3.4.....99}{2.3.4.5.6.....100}\)

\(=\frac{1}{100}\)

b) Tương tự như câu a

Ra kết quả phần b là \(\frac{101}{2}\) đúng hông?

Ta có: \(L=\left(1-\frac{1}{2}\right).\left(1-\frac{1}{3}\right)....\left(1-\frac{1}{2004}\right)\)

\(\Rightarrow L=\frac{1}{2}.\frac{2}{3}.\frac{3}{4}.....\frac{2003}{2004}\)\(=\frac{1.2.3.4....2003}{2.3.4.....2004}=\frac{1}{2004}\)

VẬY \(L=\frac{1}{2004}\)

\(L=\left(1-\frac{1}{2}\right)x\left(1-\frac{1}{3}\right)x\left(1-\frac{1}{4}\right)x.....x\left(1-\frac{1}{2003}\right)\)

\(L=\frac{1}{2}x\frac{2}{3}x\frac{3}{4}x.....x\frac{2002}{2003}\)

\(L=\frac{1x2x3x4x....x2002}{2x3x4x5x.....x2003}=\frac{1}{2003}\)

1 gấp 10 lần 1/10

1/10 : 1/100 = 10

1/100 : 1/1000 = 10

1 : 1/10 = 10

1/10 gấp 10 lần 1/100

1/100 gấp 10 lần 1/1000

k mình nha

\(\left(1-\frac{1}{2}\right)\times\left(1-\frac{1}{3}\right)\times\left(1-\frac{1}{4}\right)\times...\times\left(1-\frac{1}{2015}\right)\times\left(1-\frac{1}{2016}\right)\)

\(=\frac{1}{2}\times\frac{2}{3}\times\frac{3}{4}\times...\times\frac{2014}{2015}\times\frac{2015}{2016}\)

\(=\frac{1}{2016}\)

Giải : Ta có                (1-1/2)*(1-1/3)*(1-1/4)*....*(1-1/2015)*(1-1/2016)  

                                = 1* -(1/2+1/3+1/4+....+1/2015+1/2016)

                                = 1* - (1/2+1/2016 +1/3+1/2015 +...+1/1007)

                                = 1* -(1/2033134)

                                = -1/2033134

\(1\frac{1}{2}\text{ x }1\frac{1}{3}\text{ x }1\frac{1}{4}\text{ x }1\frac{1}{5}\)

\(=\frac{3}{2}.\frac{4}{3}.\frac{5}{4}.\frac{6}{5}\)

\(=\frac{3.4.5.6}{2.3.4.5}=\frac{6}{2}=3\)

Tính bằng cách thuận tiện nhất :

                                                \(1\frac{1}{2}\cdot1\frac{1}{3}\cdot1\frac{1}{4}\cdot1\frac{1}{5}\)

 \(=\left(1\cdot1\cdot1\cdot1\right)\cdot\left(\frac{1}{2}\cdot\frac{1}{3}\cdot\frac{1}{4}\cdot\frac{1}{5}\right)\)

 \(=1\cdot\frac{1}{120}\)

 \(=\frac{1}{120}\)

                                                       \(1\frac{1}{2}:1\frac{1}{3}:1\frac{1}{4}:1\frac{1}{5}\)

  \(=\left(1:1:1:1\right):\left(\frac{1}{2}:\frac{1}{3}:\frac{1}{4}:\frac{1}{5}\right)\)

  \(=1:30\)

  \(=\frac{1}{30}\)

1 + 1 = 2

3 + 3 = 6

5 + 5 = 10

1 + 0 = 1

99 + 1 = 100

9 + 1 = 10

5 + 5 + 5 + 5 + 5 + 5 + 5 + 5 + 5 + 1 + 1 + 1 + 1 + 1 + 1 + 1 + 5 + 5 + 5 + 7 + 7 + 7 = 88

k mk nha

2

6

10

1

100

10

83

\(\left(1-\frac{1}{2}\right).\left(1-\frac{1}{3}\right).\left(1-\frac{1}{4}\right).\left(1-\frac{1}{5}\right)\)

\(=\frac{1}{2}\cdot\frac{2}{3}\cdot\frac{3}{4}\cdot\frac{4}{5}\)

\(=\frac{1}{5}\)