linear function

1. Variables and functions

2. Linear function

3. Look at equations (groups) and inequalities from the functional point of view.

We call the amount of numerical change a variable.

Some values are always the same, which we call constants.

Generally speaking, in a changing process, if there are two variables X and Y, and each value Y of X has a unique definite value, we say that X is an independent variable and Y is a function of X. If y=b when x=a, then B is called a function value when the independent variable value is A. ..

Linear function: Generally speaking, a function with the shape y = kx (where k is constant and k is not equal to 0) is called a linear function.

When k>0, the straight line y=kx rises from left to right through the third and first quadrants, that is, y also increases with the increase of x; When k < 0, the straight line y=kx passes through the second and fourth quadrants and descends from left to right, and it is recorded that y decreases with the increase of x.

data description

1. Several common statistical tables

2. Describe the data with charts.

3. Project learning

Generally, we call the number of data in different groups the frequency of the group, and the ratio of frequency to the total number of data is the frequency.

We call the number of divided groups the number of groups, and the difference between the two endpoints of each group is the group distance.

Characteristics of some statistical charts:

1. Bar chart features: you can display the specific data of each group.

2. Fan chart features: it can show the percentage of parts in the whole.

3. Line chart features: it can display the changing trend of data.

4. Histogram features: it can display the distribution of data.

Congruent triangle

1. congruent triangles

2. Conditions in congruent triangles

3. The nature of the angular bisector

A triangle that can completely coincide is called congruent triangles.

The essence of congruent triangles;

The corresponding edges of 1. congruent triangles are equal.

2. The corresponding angles of congruent triangles are equal.

Congruent triangles's judgment theorem;

1. There are three equilateral triangular congruences (SSS).

2. Two sides and their included angles correspond to the congruence (SAS) of two triangles.

3. The congruence (ASA) corresponding to two corners and two sides of two triangles.

4. congruence of two triangles, in which two angles and the corresponding sides of one angle are equal.

5. The hypotenuse and the right-angled side correspond to the congruence (HL) of two right-angled triangles.

Properties of angular bisector:

The distance between the point on the bisector of an angle and both sides of the angle is equal.

Axial symmetry

1. Axisymmetric

2. Axisymmetric transformation

3. isosceles triangle

The parts on both sides of a straight line can overlap each other. This figure is called an axisymmetric figure, and this straight line is its axis of symmetry.

A straight line that passes through the midpoint of a line segment and is perpendicular to the line segment is called the midline of the line segment.

Integral expression

Addition and subtraction of 1. algebraic expressions

2. Multiplication of algebraic expressions

3. Multiplication formula

4. Division of algebraic expressions

5. Factorization