Articles of constants

What is circumradius $R$ of the great disnub dirhombidodecahedron, or Skilling's figure?

The vertices of a uniform polyhedron all lie on a sphere. Out of curiosity, I looked at the circumradius $R$ of the $75$ polyhedra (non-prism) in the list (which assumed side $a=1$). For irrational $R$, almost all were roots of quadratics, quartics, and a few sextics that can factor over a square root: $\sqrt{2},\sqrt{3},\sqrt{5},\sqrt{7},\sqrt{11}$ (and […]

Why is it not known if Mill's constant is rational or irrational?

The following text appears in the Mill’s constant definition at the Wikipedia: There is no closed-form formula known for Mills’ constant, and it is not even known whether this number is rational (Finch 2003). And then refers to Finch: Library of Congress Cataloging in Publication Data , Finch, Steven R., 1959- Mathematical constants / Steven […]

Two questions about Euler's number $e$

I am on derivatives at the moment and I just bumped into this number $e$, “Euler’s number” . I am told that this number is special especially when I take the derivative of $e^x$ , because its slope of any point is 1. Also it is an irrational ($2.71828\ldots$) number that never ends, like $\pi$. […]

Another simple rule satisfied by the Fibonacci $n$-step constants?

Given, $$x^n(2-x)=1\tag1$$ for $n=2,3,4,\dots$ $$(x-1)(x^2-x-1)=0\\ (x-1)(x^3-x^2-x-1)=0\\ (x-1)(x^4-x^3-x^2-x-1)=0$$ the roots of which are the golden ratio, the tribonacci constant, the tetranacci constant, and so on. Q: Is it true that for all integer $n>1$, if $y=x^{-1}$ then, $$2y\,(1-y^{n-1})(1-y^{2n+2}) = (1-y^{n+1})^3\tag2$$ and $$(1-y^{n-1})(1-y^{2n+2})^2 = (1-y^{n+1})^4\tag3$$ such that the RHS is a cube and fourth power, respectively? P.S. […]

What are the uses of Euler's number $e$?

People make such a big deal of the number $e$. I do not get why it is so important, other than the fact that $\ln(x)=\log_e(x)$. People say it is used all over mathematics and such, but they never give me examples. Where is the number $e$ used? Also, how did Euler come up with the […]

Are my calculations of a recursive prime-generating function based on logarithms correct?

I am trying to devise a recursive prime-generating function following an intuition of a possible analogy to Mills and Wright prime-representing functions, in the present case based on logarithms. The proposed prime generating function $f(n)$ will provide not a subset but the complete set of primes being $f(1)=2$, $f(2)=3$, $f(3)=5$… and the prime-generating constant will […]

Polyhedral symmetry in the Riemann sphere

I found an interesting set of constants while exploring the properties of nonconstant functions that are invariant under the symmetry groups of regular polyhedra in the Riemann sphere, endowed with the standard chordal metric. The simplest functions I have found posessing these symmetries are rational functions, with zeroes at the vertices of a certain inscribed […]

Difference between variables, parameters and constants

I believe the following 4 questions I have, are all related to eachother. Question 1: Of course I’ve been using constants, variables and parameters for a long time, but I sometimes get confused with the definition. It seems to me that these terms are used very loosely. Let’s say we have a second degree polynomial […]

What is the value of the nested radical $\sqrt{1+2\sqrt{1+3\sqrt{1+4\sqrt{1+\dots}}}}$?

The closed-forms of the first three are well-known, $$x_1=\sqrt{1+\sqrt{1+\sqrt{1+\sqrt{1+\dots}}}}\tag1$$ $$x_2=\sqrt[3]{1+\sqrt[3]{1+\sqrt[3]{1+\sqrt[3]{1+\dots}}}}\tag2$$ $$x_3=\sqrt{1+2\sqrt{1+3\sqrt{1+4\sqrt{1+\dots}}}}\tag3$$ $$x_4=\sqrt[3]{1+2\sqrt[3]{1+3\sqrt[3]{1+4\sqrt[3]{1+\dots}}}}=\;???\tag4$$ with $x_1$ the golden ratio, $x_2$ the plastic constant, and $x_3=3\,$ (by Ramanujan). Questions: Trying to generalize $x_3$, what is the value of $x_4$ to a $100$ or more decimal places? (The Inverse Symbolic Calculator may then come in handy to figure out […]

An amazing approximation of $e$

As we can read in Wolfram Mathworld’s article on approximations of $e$, the base of natural logarithm, An amazing pandigital approximation to e that is correct to $18457734525360901453873570$ decimal digits is given by $$\LARGE \left(1+9^{-4^{6 \cdot 7}}\right)^{3^{2^{85}}}$$ found by R. Sabey in 2004 (Friedman 2004). The cited paragraph raises two natural questions. How was it […]