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author | dos-reis <gdr@axiomatics.org> | 2007-08-14 05:14:52 +0000 |
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committer | dos-reis <gdr@axiomatics.org> | 2007-08-14 05:14:52 +0000 |
commit | ab8cc85adde879fb963c94d15675783f2cf4b183 (patch) | |
tree | c202482327f474583b750b2c45dedfc4e4312b1d /src/input/asec.input.pamphlet | |
download | open-axiom-ab8cc85adde879fb963c94d15675783f2cf4b183.tar.gz |
Initial population.
Diffstat (limited to 'src/input/asec.input.pamphlet')
-rw-r--r-- | src/input/asec.input.pamphlet | 204 |
1 files changed, 204 insertions, 0 deletions
diff --git a/src/input/asec.input.pamphlet b/src/input/asec.input.pamphlet new file mode 100644 index 00000000..82907431 --- /dev/null +++ b/src/input/asec.input.pamphlet @@ -0,0 +1,204 @@ +\documentclass{article} +\usepackage{axiom} +\usepackage{amssymb} +\begin{document} +\title{\$SPAD/src/input asec.input} +\author{Timothy Daly} +\maketitle +\begin{abstract} +\end{abstract} +\eject +\tableofcontents +\eject +\section{ASC.1 Introduction} + +Let $x$ be a complex variable of $\mathbb{C} \setminus \{0\}$.The +function Inverse Secant (noted {\tt asec}) is defined by +the following second order differential equation + +$$\left(2 x^{2} - 1\right) \frac{\partial y (x)}{\partial x} + +\left(x^{3} - x\right) \frac{\partial^{2} y (x)}{\partial x^{2}} =0.$$ + +The initial conditions at $0$ are not simple to state, +since $0$ is a (regular) singular point. + +\section{ASC.2 Series and asymptotic expansions} +\subsection{ASC.2.1 Asymptotic expansion at $-1$} +\subsubsection{ASC.2.1.1 First terms} + +$$ +\begin{array}{cc} +& asec(x)\approx (\pi\ldots) + \sqrt{x + 1} +\left(-i\sqrt{2} - \frac{5 i}{12} (x + 1) \sqrt{2} - +\frac{43 i}{160} (x + 1)^{2} \sqrt{2}\right. \\ +& \quad{}\quad{}- \frac{177 i}{896} (x + 1)^{3} \sqrt{2} - +\frac{2867 i}{18432} (x + 1)^{4} \sqrt{2} - \\ +& \quad{}\quad{}\frac{11531 i}{90112} (x + 1)^{5} \sqrt{2} - +\frac{92479 i}{851968} (x + 1)^{6} \sqrt{2} - \\ +& \left.\quad{}\quad{}\frac{74069 i}{786432} (x + 1)^{7} \sqrt{2} - +\frac{11857475 i}{142606336} (x + 1)^{8} \sqrt{2}\ldots\right). +\end{array} +$$ + +\subsection{ASC.2.1 Asymptotic expansion at $0$} +\subsubsection{ASC.2.2.1 First terms} + +$$ +\begin{array}{cc} +& asec(x)\approx \\ +& \quad{}\quad{}\left(i ln(2) + \frac{i}{4} x^{2} + +\frac{3 i}{32} x^{4} + \frac{5 i}{96} x^{6} + +\frac{35 i}{1024} x^{8} + i ln(x)\ldots\right). +\end{array} +$$ + +\subsection{ASC.2.3 Asymptotic expansion at $1$} +\subsubsection{ASC.2.3.1 First terms} + +$$ +\begin{array}{cc} +& asec(x)\approx \sqrt{x - 1} +\left(\sqrt{2} - \frac{5 \sqrt{2} (x - 1)}{12} + +\frac{43 \sqrt{2} (x - 1)^{2}}{160} - \right. \\ +& \quad{}\quad{}\frac{177 \sqrt{2} (x - 1)^{3}}{896} + +\frac{2867 \sqrt{2} (x - 1)^{4}}{18432} - +\frac{11531 \sqrt{2} (x - 1)^{5}}{90112} + \\ +& \quad{}\quad{}\frac{92479 \sqrt{2} (x - 1)^{6}}{851968} - +\frac{74069 \sqrt{2} (x - 1)^{7}}{786432} + \\ +& \quad{}\quad{}\frac{11857475 \sqrt{2} (x - 1)^{8}}{142606336} - +\frac{47442055 \sqrt{2} (x - 1)^{9}}{637534208} + \\ +& \quad{}\quad{}\frac{126527543 \sqrt{2} (x - 1)^{10}}{1879048192} - +\frac{1518418695 \sqrt{2} (x - 1)^{11}}{24696061952} + \\ +& \quad{}\quad{}\frac{24295375159 \sqrt{2} (x - 1)^{12}}{429496729600} - +\frac{97182800711 \sqrt{2} (x - 1)^{13}}{1855425871872} + \\ +& \left.\quad{}\quad{}\frac{777467420263 +\sqrt{2} (x - 1)^{14}}{15942918602752} - +\frac{3109879375897 \sqrt{2} (x - 1)^{15}}{68169720922112}\ldots\right). +\end{array} +$$ + +\subsubsection{ASC.2.3.2 General form} + +$$asec(x)\approx \sqrt{x - 1} \sum_{n = 0}^{\infty} u (n) (x - 1)^{n}$$ + +The coefficients $u(n)$ satisfy the recurrence +$$ +\begin{array}{cc} +& 2 u(n) \left(\frac{1}{2} + n\right) n + +u(n - 1) \left(-\frac{1}{2} + n\right) \left(-\frac{1}{2} + 3 n\right) + +u(n - 2) \left(-\frac{3}{2} + n\right) +\left(-\frac{1}{2} + n\right) \\ +& \quad{}\quad{}=0. +\end{array} +$$ + +Initial conditions of ASC.2.3.2.2 are given by +$$ +\begin{array}{cc} +u(0)& =\sqrt{2}, \\ +u(1)& =\frac{-5\sqrt{2}}{12}. +\end{array} +$$ + +As implemented within Axiom the {\tt asec} function is +$$sec^{-1}(z) == cos^{-1}\left(\frac{1}{z}\right)$$ +<<*>>= +)spool asec.output +)set message test off +)set message auto off +)set break resume +digits(22) +)clear all + +--S 1 of 10 +asec(-2.0) +--R +--R (1) 2.0943951023 9319549230 8 +--R Type: Float +--E 1 + +--S 2 of 10 +asec(-1.5) +--R +--R (2) 2.3005239830 2186298268 6 +--R Type: Float +--E 2 + +--S 3 of 10 +asec(-1.0) +--R +--R (3) 3.1415926535 8979323846 3 +--R Type: Float +--E 3 + +--S 4 of 10 +asec(-0.5) +--R +--R >> Error detected within library code: +--R acos: argument > 1 in magnitude +--R +--R Continuing to read the file... +--R +--E 4 + +--S 5 of 10 +asec(-0.0) +--R +--R >> Error detected within library code: +--R asec: no reciprocal +--R +--R Continuing to read the file... +--R +--E 5 + +--S 6 of 10 +asec(0.0) +--R +--R >> Error detected within library code: +--R asec: no reciprocal +--R +--R Continuing to read the file... +--R +--E 6 + +--S 7 of 10 +asec(0.5) +--R +--R >> Error detected within library code: +--R acos: argument > 1 in magnitude +--R +--R Continuing to read the file... +--R +--E 7 + +--S 8 of 10 +asec(1.0) +--R +--R (4) 0.0 +--R Type: Float +--E 8 + +--S 9 of 10 +asec(1.5) +--R +--R (5) 0.8410686705 6793025577 652 +--R Type: Float +--E 9 + +--S 10 of 10 +asec(2.0) +--R +--R (6) 1.0471975511 9659774615 42 +--R Type: Float +--E 10 +)spool +)lisp (bye) + +@ +\eject +\begin{thebibliography}{99} +\bibitem{1} The Encyclopedia of Special Functions +http://algo.inria.fr/esf/function/ASC/ASC.html +\end{thebibliography} +\end{document} + |