Skip to main content

All Questions

Filter by
Sorted by
Tagged with
0 votes
1 answer
98 views

Estimating the bound of the integral over whole $\mathbb{R}$ of the Taylor remainder term?

Let $f : \mathbb{R} \to \mathbb{R}$ be a smooth function which has a smooth inverse and satisfies the estimate \begin{equation} \lvert f(x) \rvert \leq \lvert x \rvert. \end{equation} Also, let $d\mu$ ...
Isaac's user avatar
  • 3,507
7 votes
0 answers
294 views

Weaker version of the Borel lemma for vector-valued functions

Borel's lemma for Frechét-spaces $V$ says: (i) For every $(v_j)_{j \in \mathbb{N}} \in V^\mathbb{N}$ there exists a smooth $f: \mathbb{R} \to V$ such that $$f^{(j)}(0) = v_j.$$ For general locally ...
Jannik Pitt's user avatar
  • 1,484
0 votes
0 answers
116 views

Finding a square integrable dominating function for function class

problem statement For any $x \in R^d$, consider the function $$\phi(x,a) = \min_{1\leq j \leq k} \|x-a_j\|^2,$$ where $a = (a_1, \dots, a_k) \in R^{kd}$ and $\| \cdot \|$ is the $L_p$ norm for any $p ...
ato_42's user avatar
  • 11
5 votes
1 answer
384 views

Asymptotic growth of the of Taylor coefficients of the inverse of a function

Let $f(x)=\sum_{n\geq 1} c_n\cdot x^n$ be a function given by a power series. Further there is some $\alpha >1$ such that for all $n$, $c_n = \Theta(1/n^{\alpha})$. What can one say about the ...
user116726's user avatar
3 votes
2 answers
247 views

aproximate sum involving binomial coefficients

I have the problem for computing the j-derivative of a logarithm, with $j\gg1$ \begin{equation} c_j=\left.\frac{\partial^j}{\partial s^j}\log\left(1+Ae^s+Be^{2s}\right)\right|_{s=0}, \end{equation} ...
user3209698's user avatar
2 votes
2 answers
157 views

Zeros of partial sums of $(1+z)/(1-z)$ near $z=-1$

Let $p_n(z)$ be the $n^\text{th}$ partial sum of the Maclaurin series for $f(z) = (1+z)/(1-z)$. For large $n$ the zeros of $p_n$ appear to avoid the point $z=-1$: Figure: Zeros of $p_{40}$ and the ...
Antonio Vargas's user avatar
1 vote
0 answers
237 views

Asymptotics to Taylor expansions?

I posted a question on MSE about approximating Taylor series but Despite a bounty I did not receive any answers or comments. Maybe you guys can help. https://math.stackexchange.com/questions/1440931/...
mick's user avatar
  • 763
1 vote
1 answer
165 views

Estimate the scale of the power series with Poisson pdf/pmf-like terms

I would like to have an estimate for the series $$P(t) = \sum\limits_{k = 0}^\infty (e^{-t}\frac{t^k}{k!})^m,$$ where $e$ is the base of natural logarithm, $k!$ is the factorial of the integer $k$, $t$...
Erdos Yi's user avatar
  • 113
10 votes
3 answers
4k views

Estimate for tail of power series of exponential function?

I would like to have an estimate for the infinite series $$ \sum_{k=B}^\infty \frac{A^k}{k!}, $$ where $A$ is a large positive quantity and $B$ is just a little bit bigger than $A$, namely, $B = A + C ...
Greg Martin's user avatar
  • 12.8k