Problem of the Week 7-26-18: 2nd Order Nonhomogenous Linear Differential Equation [Differential Equations]

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Problem of the Week 7-19-18: Invertible Matrix [Linear Algebra]

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*Note: In the video, k² - 1 - 6(k - 1) reduces to k²- 6k + 5 NOT k² - 6k - 5

Unlucky Numbers Around the World

via GIPHY

Friday the 13^th is upon us!  Across the nation, there are people avoiding black cats, spilled salt, ladders, and broken mirrors. Not everyone, however, is scared of 13 because they have other numbers to fear. 

In honor of today, here are 6 unlucky numbers from around the world.

4 - China

In China, the number 4 is considered unlucky because it is homophonous to the word "death." Similar to how the 13^th floor is absent in many buildings in the West, the 4^th floor is often left out in China.

9 - Japan

Just like the number 4 in China, the number 9 is a bad omen in Japan because it sounds similar to the Japanese word for “torture.”

17 - Italy

The Roman numeral for 17 is XVII, and an anagram for XVII is "VIXI.” This translates to “I lived," aka “my life is over."

26  - India 

For India, tragedies and disasters have the pattern of striking on the 26^th (the 2008 Mumbai terror attack, the 2001 Gujarat earthquake, the 2004 Indian Ocean tsunami, 2008 Ahmedabad bomb blasts). For this reason, India doesn't really like the number 26. Can you blame them?

39 - Afghanistan

The number 39 is considered cursed in Afghanistan due to the fact that 39 translates to  ‘morda gow’ which means ‘dead cow” - which is slang for pimp. Since 39 is linked to prostitution, the number is largely avoided.


0888 888 888 - Bulgaria
After three people in Bulgaria with the phone number 0888 888 888 died within ten years, a Bulgarian mobile company suspended the phone number because they believed it was cursed. If you are in Bulgaria, try calling the number. Surely, no one will pick up. 

If we missed any unlucky numbers in your culture, be sure to comment below. Also, be sure to check out past blog posts about Friday the 13th. 
1. 13 Facts about the Number 13
2. Friday The 13th, Math and Music.

Sources:

https://news.nationalgeographic.com/news/2013/09/130913-friday-luck-lucky-superstition-13/

http://www.smosh.com/articles/unlucky-numbers-different-cultures-around-world

https://listverse.com/2015/03/06/10-numbers-that-launched-absurd-superstitions/

Advanced Knowledge Problem of the Week 7-12-18: Root Existence for a Polynomial [Real Analysis]

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Problem of the Week 7-10-18: A Functional Equation on Nonnegative Integers [Functional Equations]

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Advanced Knowledge Problem of the Week 7-5-18: Infinite Squares and Euler's Totient Function [Number Theory]

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Problem of the Week 7-3-18: Invariant Sums of Digits [Number Theory]

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