AT5s #4

Hello internet. Today I will be listing the top five most well known/important constants in math. If you don't like math or don't know what a constant is, well then, sorry.

5. Tau (symbol: τ)
This number is sort of well known, I guess, but it is quite important. This constant is basically twice the amount of pi. Since pi ~3.14, tau is ~6.28. But that's not only what tau means. In greek, the greek letter "τ" means the number 300. It is also sometimes means the golden ratio (1.618...), but not usually.


4. Euler's constant (symbol: γ)
This constant is pretty well known. The constant is 0.57721566490153286060651209008240243104215
933593992 and so on (that doesn't mean it repeats, I mean that it just keeps on going). This constant is used as the limiting difference between the harmonic series and the natural logarithm. Whatever the heck that means.

3. Phi (symbol: φ)
This constant isn't just a math constant. It also appears in art, and literature! Phi [usually] represents the golden ratio. (Video to explain it ↓ Credit: Khan Academy)



2. e (symbol: itself)
e is an important mathematical constant and can be defined in many ways. Usually, it's used as a variable in the compound interest equation. Like pi, e is irrational. It never ends and never repeats. Its approximation that most equations use is 2.71828.

1. Pi (symbol: π)
Of course this constant would be the most well known. Like e, pi is also irrational. The approximation that most equations use is just 3.14. It's mainly used in the equation to find the area and the circumference of a circle. In the 21st century, we (using computers) managed to find its digits in the trillionths.

Interesting fact of the day: The US playing card company ‘Bicycle’ had manufactured a playing card in WW2. That, when the card was soaked, it would reveal an escape route for POWs. These cards were Christmas presents for all POWs in Germany.