The methods to find the limit of unary function are: equivalent infinitesimal substitution; Robida's law; The product of infinitesimal and bounded function is still infinitesimal; The limit value of a continuous function is equal to its function value.

Definition of limit: between a number and a set of numbers, if there is a number that makes all the finite powers of this number less than or equal to itself, it is called the limit of this set of numbers.

Extended data:

Domain of unary function

1. unary function refers to a set of continuous changing processes with only independent variables and no dependent variables. For example, points p 1, p2, ..., pn are called the set-line segment L 1 to point N near the end of the straight line L, lm is called line segment l 1, ..., and l2 is line segment 1.

2. The length relationship between point 1 and point n is one of the special cases of line segment length relationship, so we say that the length relationship of line segment includes the relationship between point 1 and the distance between point and n-that is, the relationship between point1-n. ..

3. Draw a horizontal line M 1(m) in the plane rectangular coordinate system, and mark all points of the horizontal line on M 1(m) to form ray S 1. Let S 1 = S0, S2 = S 1, S3 = S2...Sn = S3, then M 1(m) is called the unit of point-to-line distance A 1.