1、 When a number is divided by zero, the result is undefined because, according to the laws of mathematics, division by zero is not permissible， It presents a vast range of possible outcomes, from harmless discrepancies in the program's output to major crashes or security vulnerabilities. Moreover, in geometry, the tangent of 90 degrees or 270 degrees is undefined, because those angles produce vertical lines for which no slope exists， In programming languages like JavaScript, undefined is a primitive value automatically assigned to variables that are declared but not yet assigned a value.In the realm of mathematics, 'undefined' forms an integral part of its vocabulary, indicating outcomes or equations that cannot produce a definite value， Undefined behavior in programming languages like C and C++, denote the outcomes of code that doesn't comply with the language's syntax rules, and in this context, the term is indicative of a serious programming error.
2、 Yet, undefined in mathematics and computer science, despite its ambiguity, is not merely a void or error, but a critical concept that creates room for growth and discovery; a testament to the evolving and expanding nature of these fields. Similarly, the field of computer science often uses 'undefined' to refer to variables that have not yet been assigned a particular value, or functions that do not return a value， Furthermore, results from queries in database management where no matching record or data is found are also considered undefined.
