1. Basic knowledge of algebra: including basic concepts and operation rules such as real number, complex number, polynomial, exponent and logarithm. This knowledge is the basis of understanding the limit of function.
2. Basic knowledge of geometry: including basic concepts such as point, line, surface and angle, as well as graphic representation of straight lines and curves. This knowledge is helpful to understand the changing trend of function images.
3. Basic knowledge of trigonometric functions: including basic concepts and properties such as sine, cosine and tangent, and basic formulas of trigonometric functions. This knowledge is very useful in dealing with the function limit problem related to angle.
4. Basic knowledge of derivative and differential: derivative and differential are tools to study the rate of change of functions, which are very important for understanding the concept and properties of function limits. Beginners need to understand the definition, properties and calculation methods of derivative, as well as the concept and application of differential.
5. Basic concepts of limit: Beginners need to master the basic concepts and properties of limit before learning function limit, including infinity, infinitesimal, existence of limit, uniqueness of limit and so on. This knowledge lays the foundation for learning the limit of function.
6. Basic knowledge of inequality: In the process of learning the limit of a function, inequalities are often used to prove the existence and uniqueness of the limit. Therefore, beginners need to understand the basic concepts and properties of inequalities, such as pinch theorem, monotone bounded principle and so on.
7. Basic mathematical symbols and expressions: Learning the limit of a function requires mastering various mathematical symbols and expressions, such as limit symbols (lim), infinite symbols (∞) and infinitesimal symbols (-∞). These symbols and expressions are the key to understand and calculate the limit of functions.
In short, learning the limit of a function requires some preparatory knowledge in algebra, geometry, trigonometric functions, derivative differentiation, limits, inequalities and mathematical symbols. Only by mastering these basic knowledge can we better understand and apply the concept and method of function limit.