Skip to main content

All Questions

Filter by
Sorted by
Tagged with
6 votes
4 answers
780 views

roots of higher derivatives of exponential

Consider the Gaussian function $f(z)=e^{-z^2}$ which has no zeros on the complex domain. Let $D$ denote derivative w.r.t. the variable $z$. Question. Is it true that $D^nf(z)=0$ has only real roots ...
T. Amdeberhan's user avatar
4 votes
2 answers
443 views

Largest absolute value of a polynomial of degree $n$ on $\{0,1,\ldots,n\}$

Consider a polynomial $P_n(x)\in\mathbb{R}[x]$, of degree $n\geq1$, of the form $$P_n(x)=c_0+c_1x+c_2x^2+\cdots+c_{n-1}x^{n-1}+x^n.$$ To illustrate the question, take $P_1(x)=c_0+x$ so that $P_1(0)=...
T. Amdeberhan's user avatar
4 votes
2 answers
334 views

what is this sum of squares of algebraic functions?

This question is inspired by the MO query here, although it has no direct implications. Define the family of polynomial functions $$f_n(x)=n^2x^{n-1}-\frac{d}{dx}\left(\frac{x^n-1}{x-1}\right),$$ and ...
T. Amdeberhan's user avatar