Formula:

1 degree of monomial: the sum of the indices of all letters in a monomial is called the degree of this monomial.

The degree of the term with the highest degree in a polynomial is called the degree of the polynomial.

The essence of algebraic addition and subtraction is to merge similar terms in algebraic expressions. If there are brackets, remove them first, and then merge similar items.

Divided by the same base, the base remains the same and the index is subtracted.

Two: parallel lines and intersecting lines

Formula:

Complementary angle and complementary angle law: 1 If the sum of two angles is a right angle, they are said to be complementary angles. If the sum of two angles is a right angle, these two angles are called complementary angles.

Three: data in life

1 significant digit: for an approximation, all digits from the first non-zero digit on the left to the most accurate digit are called significant digits of this number.

2 parallel lines like this, two lines that will not intersect are two parallel lines, which are called parallel lines for short. Quadrilateral: Two groups of opposite sides are parallel.

3 statistical chart: 1 bar statistical chart: bar statistical chart represents a certain quantity with unit length, draws straight lines with different lengths according to the quantity, and then arranges these bars in a certain order. It is easy to see various numbers from the bar chart.

Bar charts can be divided into simple bar charts and composite bar charts. The former only represents the data of 1 item, while the latter can represent multiple items of data at the same time.

2 broken line statistical chart: broken line statistical chart represents a certain quantity with unit length, and draws points according to this quantity, and then connects the points in turn with line segments to show that the statistical quantity increases or decreases with the rise or fall of broken lines. The broken-line statistical chart can not only show the quantity, but also clearly show the change of the quantity. Broken-line statistical charts are divided into single or multi-models.

Sector statistics chart: Sector statistics chart uses the whole circle and each sector in the circle to represent the total.

The size of represents the percentage of each part in the total. The relationship between the number of each part and the total number can be clearly expressed through the fan-shaped statistical chart. Use the area of the whole circle to represent the total (unit 1), and use the sector area of the circle to represent the percentage of each part in the total. Function: It can clearly reflect the relationship between the quantity of each part of the book and the total. The relationship between the sector area and its corresponding central angle is that the larger the sector area, the greater the degree of the central angle. The smaller the sector area, the smaller the degree of the central angle. The relationship between degree and percentage of fan-shaped central angle is: degree of central angle = percentage *360 degrees. Sector statistical charts can also be drawn as cylinders.

Four: Triangle

There are three kinds of triangles, acute triangle: not a triangle with acute angles, but all three angles are acute angles, such as an equilateral triangle and an acute triangle. Right triangle: A triangle with an angle of 90 degrees is a right triangle. Obtuse triangle: A triangle with an obtuse angle is called an obtuse triangle. Any triangle has at most three acute angles; There is at most one obtuse angle; There is at most one right angle.

A triangle has three midlines, all of which are inside the triangle and intersect at one point. The center line of a triangle is a line segment.