Question

so sánh 1/1.2+1/2.3+1/3.4+..........1/49.50 với 1 giúp mk nha cảm ơn 

Answer 1

đặt A=1/1.2+1/2.3+1/3.4+..........1/49.50

\(A=1-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+...+\frac{1}{49}-\frac{1}{50}\)

\(A=1-\frac{1}{50}<1\)

vậy A<1

Answer 2

1/1.2 + 1/2.3 + 1/3.4 + ... + 1/49.50

1 - 1/2 + 1/2 - 1/3 + 1/3 - 1/4 + ... + 1/49 - 1/50

1 - 1/50 < 1

Answer 3

1/1.2 + 1/2.3 + 1/3.4 + ...... + 1/49.50

1 - 1/2 + 1/2 - 1/3 + 1/3 - 1/4 + ..... + 1/49 - 1/50

1 - 1/50 < 1

Answer 4

1/1.2 + 1/2.3 + 1/3.4 + ... + 1/49.50

= 1 - 1/2 + 1/2 - 1/3 + 1/3 - 1/4 + ... + 1/49 - 1/50

= 1 - 1/50

= 49/50.

49/50 < 50/50

Mà 50/50 = 1

=> 49/50 < 1

Answer 5

\(\frac{1}{1.2}+\frac{1}{2.3}+\frac{1}{3.4}+..+\frac{1}{49.50}\)

\(=\frac{1}{1}-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-\frac{1}{4}+..+\frac{1}{49}-\frac{1}{50}\)

\(=1-\frac{1}{50}\)

\(=\frac{49}{50}\)

\(\Rightarrow\frac{49}{50}<1\)

Answer 6

1/1.2 + 1/2.3 + 1/3.4 + ... + 1/49.50

= 1 - 1/2 + 1/2 - 1/3 + 1/3 - 1/4 + ... + 1/49 - 1/50

= 1 - 1/50 = 49/50. 49/50 < 50/50

Mà 50/50 = 1 => 49/50 < 1 

Answer 7

\(\frac{1}{1\cdot2}+\frac{1}{2\cdot3}+...+\frac{1}{49\cdot50}\)

\(=1-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+...+\frac{1}{49}-\frac{1}{50}\)

\(=1-\frac{1}{50}<1\)

Answer 8

1/1.2+1/2.3+1/3.4+...+1/49.50

=1-1/2+1/2-1/3+1/3-1/4+...+1/49-1/50

=1-1/50

=49/50

do49/50<50/50

suy ra 1/1.2+1/2.3+1/3.4+...+1/49.50<1

Answer 9

1/1.2 + 1/2.3 + 1/3.4 + ... + 1/49.50

= 1 - 1/2 + 1/2 - 1/3 + 1/3 - 1/4 + ... + 1/49 - 1/50

= 1 - 1/50 = 49/50. 49/50 < 50/50

Mà 50/50 = 1 => 49/50 < 1