Derivation of the Series Expansion

Oct 13, 2025 by wbrum.org 98 views

Introduction

In the field of mathematics, particularly in the realm of calculus and analysis, series expansions play a crucial role in understanding and solving complex problems. One such problem involves the series expansion of the expression $\frac{\sqrt{\theta/2}}{\sin(\sqrt{\theta/2})}$ . This expression arises in various contexts, including the study of goodness-of-fit tests on a circle, as seen in Watson's 1961 paper "Goodness-Of-Fit Tests on a Circle". In this article, we will delve into the series expansion of this expression, exploring its derivation and properties.

Background and Context

The expression $\frac{\sqrt{\theta/2}}{\sin(\sqrt{\theta/2})}$ is a key component in the study of goodness-of-fit tests on a circle. In this context, the expression is used to represent a ratio of two functions, where the numerator involves the square root of a fraction, and the denominator involves the sine of a square root function. The goal is to find a series expansion for this expression, which can be used to simplify and analyze the underlying mathematical relationships.

Derivation of the Series Expansion

To derive the series expansion of $\frac{\sqrt{\theta/2}}{\sin(\sqrt{\theta/2})}$ , we can start by expressing the expression in a more manageable form. One approach is to use the Taylor series expansion of the sine function, which is given by:

\sin(x) = x - \frac{x^3}{3!} + \frac{x^5}{5!} - \frac{x^7}{7!} + \cdots

Using this expansion, we can rewrite the expression $\frac{\sqrt{\theta/2}}{\sin(\sqrt{\theta/2})}$ as:

\frac{\sqrt{\theta/2}}{\sin(\sqrt{\theta/2})} = \frac{\sqrt{\theta/2}}{\sqrt{\theta/2} - \frac{(\sqrt{\theta/2})^3}{3!} + \frac{(\sqrt{\theta/2})^5}{5!} - \frac{(\sqrt{\theta/2})^7}{7!} + \cdots}

Simplifying the Expression

To simplify the expression, we can start by canceling out the common factor of $\sqrt{\theta/2}$ in the numerator and denominator. This leaves us with:

\frac{1}{1 - \frac{(\sqrt{\theta/2})^2}{3!} + \frac{(\sqrt{\theta/2})^4}{5!} - \frac{(\sqrt{\theta/2})^6}{7!} + \cdots}

Series Expansion

Using the binomial theorem, we can expand the denominator of the expression as:

1 - \frac{(\sqrt{\theta/2})^2}{3!} + \frac{(\sqrt{\theta/2})^4}{5!} - \frac{(\sqrt{\theta/2})^6}{7!} + \cdots = \left(1 - \frac{\theta}{6} + \frac{\theta^2}{120} - \frac{\theta^3}{5040} + \cdots\right)^{-1/2}

Inverse Laplace Transform

The series expansion of $\frac{\sqrt{\theta/2}}{\sin(\sqrt{\theta/2})}$ can be used to find the inverse Laplace transform of the expression. The inverse Laplace transform is given by:

\mathcal{L}^{-1}\left\{\frac{\sqrt{\theta/2}}{\sin(\sqrt{\theta/2})}\right\} = \frac{1}{\pi} \int_0^\infty \frac{\sqrt{\theta/2}}{\sin(\sqrt{\theta/2})} e^{-\theta t} d\theta

Conclusion

In this article, we have derived the series expansion of the expression $\frac{\sqrt{\theta/2}}{\sin(\sqrt{\theta/2})}$ . The series expansion is given by:

\frac{\sqrt{\theta/2}}{\sin(\sqrt{\theta/2})} = \left(1 - \frac{\theta}{6} + \frac{\theta^2}{120} - \frac{\theta^3}{5040} + \cdots\right)^{-1/2}

The series expansion can be used to simplify and analyze the underlying mathematical relationships in the study of goodness-of-fit tests on a circle. Additionally, the series expansion can be used to find the inverse Laplace transform of the expression.

References

Watson, G. S. (1961). "Goodness-Of-Fit Tests on a Circle." Biometrika, 48(3-4), 327-339.

Introduction

In our previous article, we derived the series expansion of the expression $\frac{\sqrt{\theta/2}}{\sin(\sqrt{\theta/2})}$ . In this article, we will address some of the frequently asked questions related to the series expansion and provide additional insights into the underlying mathematics.

Q: What is the significance of the series expansion of $\frac{\sqrt{\theta/2}}{\sin(\sqrt{\theta/2})}$ ?

A: The series expansion of $\frac{\sqrt{\theta/2}}{\sin(\sqrt{\theta/2})}$ is significant in the study of goodness-of-fit tests on a circle. The expression arises in the context of statistical analysis and is used to represent a ratio of two functions. The series expansion provides a simplified form of the expression, which can be used to analyze and understand the underlying mathematical relationships.

Q: How is the series expansion of $\frac{\sqrt{\theta/2}}{\sin(\sqrt{\theta/2})}$ used in practice?

A: The series expansion of $\frac{\sqrt{\theta/2}}{\sin(\sqrt{\theta/2})}$ is used in practice to simplify and analyze the underlying mathematical relationships in the study of goodness-of-fit tests on a circle. The series expansion can be used to find the inverse Laplace transform of the expression, which is a crucial step in statistical analysis.

Q: What are the limitations of the series expansion of $\frac{\sqrt{\theta/2}}{\sin(\sqrt{\theta/2})}$ ?

A: The series expansion of $\frac{\sqrt{\theta/2}}{\sin(\sqrt{\theta/2})}$ is an approximation of the original expression and is valid only for certain values of $\theta$ . The series expansion is not valid for all values of $\theta$ , and the approximation may not be accurate for large values of $\theta$ .

Q: How can the series expansion of $\frac{\sqrt{\theta/2}}{\sin(\sqrt{\theta/2})}$ be generalized to other expressions?

A: The series expansion of $\frac{\sqrt{\theta/2}}{\sin(\sqrt{\theta/2})}$ can be generalized to other expressions by using the same techniques and methods. The key is to identify the underlying mathematical relationships and to use the series expansion to simplify and analyze the expression.

Q: What are some common applications of the series expansion of $\frac{\sqrt{\theta/2}}{\sin(\sqrt{\theta/2})}$ ?

A: The series expansion of $\frac{\sqrt{\theta/2}}{\sin(\sqrt{\theta/2})}$ has several common applications in statistics and mathematics. Some of the common applications include:

Goodness-of-fit tests on a circle
Statistical analysis of circular data
Inverse Laplace transform
Series expansion of other expressions

Q: How can the series expansion of $\frac{\sqrt{\theta/2}}{\sin(\sqrt{\theta/2})}$ be used to solve problems in statistics and mathematics?

A: The series expansion of $\frac{\sqrt{\theta/2}}{\sin(\sqrt{\theta/2})}$ can be used to solve problems in statistics and mathematics by simplifying and analyzing the underlying mathematical relationships. The series expansion can be used to find the inverse Laplace transform of the expression, which is a crucial step in statistical analysis.

Conclusion

In this article, we have addressed some of the frequently asked questions related to the series expansion of $\frac{\sqrt{\theta/2}}{\sin(\sqrt{\theta/2})}$ . We have provided additional insights into the underlying mathematics and discussed some of the common applications of the series expansion. The series expansion of $\frac{\sqrt{\theta/2}}{\sin(\sqrt{\theta/2})}$ is a powerful tool in statistics and mathematics, and its applications are diverse and widespread.

References

Watson, G. S. (1961). "Goodness-Of-Fit Tests on a Circle." Biometrika, 48(3-4), 327-339.
Laplace Transform: A Comprehensive Introduction
Series Expansion: A Guide to Derivation and Properties
Inverse Laplace Transform: A Tutorial