Book "Mathematics at 4 h. H. 4. Differential Equations and Systems . Rows" by Kondratiev N. A. , Meleshko A. N. , Bokut L. In. and Litovko A. A. This is not just a textbook, but a real find for everyone who seeks to understand the world of mathematical laws more deeply. The fourth part of this large-scale edition is devoted to the most important topics, such as differential equations, systems of equations and series, which are fundamental in mathematics and its applications. This book will become an indispensable assistant for students, graduate students and teachers, as well as for anyone interested in mathematics at a deeper level. If you are a student of technical or natural science, then you will certainly face the need to study these topics. The book will help you not only to prepare for exams, but also to develop analytical thinking, which is extremely important in any professional activity. Authors, each of whom is an expert in their field, offer readers accessible and logically structured material. They use clear and understandable examples, which makes it easy to assimilate even the most complex concepts. In the book you will find a lot of problems for self-solution, which will help to consolidate the knowledge gained and develop the skills of practical application of the theory. Topics raised in "Mathematics at 4 h. H. 4", covering a wide range of issues. Differential equations, for example, play a key role in mathematical modeling of various processes, from mechanics to economics. Systems of equations allow solving more complex problems where several variables interact. Rows, in turn, are the basis for studying functions and their properties. These topics are not only relevant for study, but also find application in real life, which makes their study especially important. The book is distinguished by its special style of presentation .. The authors strive to make the material not only accessible, but also fascinating. They use a lively and understandable language, which avoids the unnecessary formality often inherent in teaching aids. This makes reading not only useful, but also enjoyable. In addition, the book features illustrations and graphics that help visualize complex ideas and concepts. If you are already familiar with the previous parts of the series "Mathematics at 4 h. The fourth part will be a logical continuation of your mathematical journey. And if you are just starting to get acquainted with this series, then you will find a fascinating immersion in the world of mathematics, where each new chapter opens up new horizons for you. Book "Mathematics at 4 h. H. 4. Differential Equations and Systems . Rows is not just a manual, but a real key to understanding complex mathematical concepts. It is suitable for both students and teachers, as well as for anyone who wants to expand their knowledge in the field of mathematics. Do not miss the opportunity to take a step towards new knowledge and skills that will open doors for you to the world of science and technology.