Bøker av Xing Zhou

An easy to follow guide to develop front office trading applications using C#.

Official site with more information and practice: www.mathallstar.org.Competition math is not about complicated theorems and formulas. It is more about how to analyze in order to solve challenging problems. Thus, merely remembering hundreds of theorems and formulas is far from sufficient to win math competitions. Students must be able to think effectively.This book aims to help students understand some frequently used methods of proof and improve their ability to think effectively. Contents in this book are organized based on methodologies rather than specific subjects. Consequently, examples and practice problems presented in each chapter may cover many different subjects. For example, the chapter Symmetry contains problems relating to polynomial factorization, equation, counting, and so on. Despite of being belong to different subjects, all of these problems can be solved by exploiting their intrinsic symmetric properties. Readers should focus on learning how to identify and utilize such properties. This analysis skill is a critical one to develop in addition to specific subject math knowledge.All the methodologies discussed in this book are intuitive and easy to understand. Some of them may be taught in classroom such as mathematical induction and proof by contradiction. Others may be not. Regardlessly, all of them are powerful to solve many competition problems. In addition, mastering the art of thinking not only is helpful for improving students' contest performance during school years, but also has positive impacts on their future. For example, some problems in this book originate from various job interviews. Being able to think effectively in order to solve such interview and other practical problems is certainly beneficial to their future.More information can be found at www.mathallstar.org.

There are hundreds of, if not more, geometry theorems. It is nearly impossible and definitely not necessary to remember all of them. Instead, students should focus on those must know theorems. In addition to remembering these theorems themselves, it is also important to study their typical applications. This book covers both areas.Each chapter of this book introduces a collection of related theorems. Those essential ones are discussed in the body contents. Students must remember all of them. Some additional theorems are included in the practice. They are good to know and remember.Practices are intended to demonstrate these theorems' typical applications. Many of them are classical problems. Some conclusion are well-known and can be practically treated as theorems. As such, students are encouraged to remember such conclusions as well.More information can be found at http: //www.mathallstar.org/

Practice makes perfect. This book contains 100 problems focusing on binomial expansion (including multinomial expansion) and combinatorial identities (such as hockey stick identity, Vandermonde identity and so on). In addition to introducing these theorems and identities themselves, this book also discusses various typical problems and techniques that are related to these two topics. For more information, please visit https: //www.mathallstar.org/.

Welcome to the Math All Star series! These books are for middle school and high school students who are motivated to participate in math competitions such as MathCounts, AMC, and AIME. Their coaches may also find these books useful.The website, http: //www.mathallstar.org, provides extra practice problems and serves as a highly recommended supplemental learning resource.Indeterminate EquationIndeterminate equations is a popular subject in math competitions at all levels, from AMC 8 to IMO. For example, in 2015 alone, both IMO and USAMO have an indeterminate equation problem out of 6 in total. Meanwhile, AIME and AMC12/10/8 also have various related questions.Despite its popularity, how to solve indeterminate equations is rarely discussed in classrooms. As a result, many students are lack of necessary knowledge and skills to tackle such problems. This book is to discuss various types of indeterminate equations and corresponding solving techniques. Upon completing this book, readers should be able to recognize and solve these indeterminate equations comfortably.Table of contents and pre-assessment are both available at the website www.mathallstar.com.

Official site with more information and practice: www.mathallstar.org.Trigonometry is an important subject in mathematics. It relates to many other subjects such as geometry, coordinate geometry, complex number, and so on. Therefore, trigonometric problems appear in almost every AMC12 or above competition either explicitly or implicitly. In addition, students attending lower level competition may find trigonometry can offer valuable alternative solutions to some geometry problems.In order to be proficient in trigonometry, it is necessary to memorize some formulas. However, there are hundreds, if not thousands, of trigonometric formulas. It is practically impossible and often unnecessary to remember all of them. Therefore, it is critical to know what formulas are essential and thus have to be remembered. Accordingly, the first objective of this book is to help students understand and remember those essential formulas.Remembering a sufficient number of formulas may help students achieve high scores in school tests. However, it is not sufficient to win math competitions. Students will have to master relevant techniques and be able to choose the most appropriate formula to solve particular problems. Let's take the following expression as an example: \begin{equation}\label{eq_ex}\cos 20^\circ \cos 40^\circ \cos 80^\circ\end{equation}\indent The value of this expression can be calculated in multiple ways. A classic technique is to multiply it by $\sin 20^\circ$. The result can be obtained by applying the double angle formula a few times. An alternative, relatively less known, solution is to apply the triple angle formula. This solution can produce the result immediately. Both approaches are workable in this case. Each of them can be used to tackle some generalized formed of \myJustRef{eq_ex}. As such, it is important for students to know all the relevant techniques and which one to choose in a particular case. Accordingly, the second objective of this book is to illustrate important techniques and to explain when to use them. In order to achieve this, some sample problems will appear repeatedly when different techniques are discussed. This will help students understand the pros and cons of different techniques when tacking specific problems.Upon completing this book, students should have the necessary basis for solving trigonometry problems in math competitions. In order to maximize learning results, students should attempt all the examples and practice problems once again after finishing the whole book. This will be helpful to re-enforce those techniques discussed and also offer a chance for students to reflect appropriateness of different techniques to solve particular problems

Welcome to the Math All Star series! These books are for middle school and high school students who are motivated to participate in math competitions such as MathCounts, AMC, and AIME. Their coaches may also find these books useful.The website, www.mathallstar.org, provides extra practice problems and serves as a highly recommended supplemental learning resource.CountingYou think everybody can count? Take a look at some counting problems available on the aforementioned website, and you might just think differently.Counting problems appear in all levels of math competitions. It is one type of problems that senior students and even adults may not necessarily do better on than well-trained junior students. This is because counting problems usually do not involve complex theorems or formulas. Rather, they demand a systematic and analytical approach, which can be mastered with the structured training that this book offers.The first half of the book teaches essential counting principles and formulas by going over easy-to-follow examples. After identifying hidden pitfalls and common misunderstandings, this book offers tips on how to avoid those traps. The second half covers well-established patterns in counting problems and introduces different ways to tackle each type. Mastering these techniques has proven to be very powerful and effective in improving problem solving skills.Each chapter starts with examples and progresses with inspiring questions, followed by detailed, step-by-step reasoning. When there are multiple solutions, their similarities and differences are examined to provide students with greater insights. Each chapter contains practice problems with full solutions provided at the end of the book.Upon completing this book, students will be able to: Analyze and approach problems like trained prosIdentify common pitfalls in problem solving, andRecognize frequently used patterns and apply appropriate techniques