MHB Is the Inequality of Series Proven with 1 to 99 and 2 to 100?

  • Thread starter Thread starter Albert1
  • Start date Start date
  • Tags Tags
    Inequality
Click For Summary
The discussion centers on proving the inequality between the product of odd numbers from 1 to 99 and the product of even numbers from 2 to 100. The goal is to show that the ratio of these products is greater than 1/(10√2). Participants engage in mathematical reasoning and calculations to establish this inequality. The conversation highlights the significance of understanding series and products in mathematical proofs. The conclusion emphasizes the validity of the inequality as a key mathematical result.
Albert1
Messages
1,221
Reaction score
0
prove :
$\dfrac {1\times 3 \times 5\times------\times 99}{2\times 4\times 6\times --\times {100}}>\dfrac {1}{10\sqrt 2}$
 
Mathematics news on Phys.org
Albert said:
prove :
$\dfrac {1\times 3 \times 5\times------\times 99}{2\times 4\times 6\times --\times {100}}>\dfrac {1}{10\sqrt 2}$
Let

$A= \frac{3}{4}*\frac{5}{6}\cdots\frac{99}{100}$
$B = \frac{2}{3}*\frac{4}{5}\cdots\frac{98}{99}$
In the above products each term of A is > B pairwise so A > B

$A * B = \frac{2}{100}$ and hence $A \gt\sqrt{(\frac{2}{100})}$

hence $ A \gt\frac{\sqrt{2}}{10}$

hence given expression which is $\frac{A}{ 2}$

so $\gt\dfrac{1}{10\sqrt{2}}$
 
kaliprasad said:
Let

$A= \frac{3}{4}*\frac{5}{6}\cdots\frac{99}{100}$
$B = \frac{2}{3}*\frac{4}{5}\cdots\frac{98}{99}$
In the above products each term of A is > B pairwise so A > B

$A * B = \frac{2}{100}$ and hence $A \gt\sqrt{(\frac{2}{100})}$

hence $ A \gt\frac{\sqrt{2}}{10}$

hence given expression which is $\frac{A}{ 2}$

so $\gt\dfrac{1}{10\sqrt{2}}$
very nice !
 
Here is a little puzzle from the book 100 Geometric Games by Pierre Berloquin. The side of a small square is one meter long and the side of a larger square one and a half meters long. One vertex of the large square is at the center of the small square. The side of the large square cuts two sides of the small square into one- third parts and two-thirds parts. What is the area where the squares overlap?

Similar threads

Replies
1
Views
1K
  • · Replies 8 ·
Replies
8
Views
2K
  • · Replies 1 ·
Replies
1
Views
1K
  • · Replies 2 ·
Replies
2
Views
1K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 1 ·
Replies
1
Views
1K
  • · Replies 2 ·
Replies
2
Views
1K
  • · Replies 1 ·
Replies
1
Views
1K
  • · Replies 2 ·
Replies
2
Views
1K
  • · Replies 2 ·
Replies
2
Views
2K