Junior high school students must recite the following formula:

1, square difference formula: the sum of two numbers multiplied by the difference of two numbers equals the square difference of two numbers. Complete square formula: the first square and the last square, twice the first and the last one in the center; Add the squares of sum and then add the difference, and subtract the squares of difference and then add them. Pythagorean Theorem: The sum of squares on both sides of a right triangle is equal to the square of the hypotenuse.

2. Multiplication and factorization: Multiply the single item, and multiply it by the coefficient and the same base power respectively; Polynomial multiplication, first multiply the draft, then multiply and divide, and finally add and subtract. Power: constant radix, exponential multiplication. Power of product: multiply each factor in the product separately, and then multiply the obtained power.

3. Power of fraction: Calculate the power of numerator and denominator respectively. The formula of the circumference of a circle: C=2πr, where π represents pi and r represents the radius of the circle. The area formula of a circle: S=πr? , where π represents pi and r represents the radius of a circle. The area formula of triangle: S= 1/2absinC, where a, b and c respectively represent the lengths of three sides of triangle, and c represents the included angle of two sides.

4. The area formula of trapezoid: S=(a+b)÷2×h, where A and B represent the lengths of the upper and lower bases of trapezoid respectively, and H represents the height of trapezoid. The area of parallelogram is the same as S=absinC, where a and b represent the length of two sides of parallelogram and c represents the included angle of two sides.

5. The area formula of the diamond: S= 1/2acsinB, where A and C respectively represent the length of the two diagonal lines of the diamond, and B represents the included angle between the two diagonal lines. Square area formula: S=a? Where a represents the side length of a square.

Mathematics related knowledge

1. Definition and nature of mathematics: Mathematics is a discipline that studies concepts such as quantity, structure, change and space, involving various concepts such as infinity, limit, continuity and discreteness, as well as operations and formulas such as addition, subtraction, multiplication and division, exponent, logarithm and trigonometric function. Mathematics is abstract, rigorous and widely used.

2. Branches and fields of mathematics: Mathematics mainly includes basic branches such as algebra, geometry, probability theory and statistics, as well as various fields of applied mathematics. Algebra is a subject that studies the properties and operations of numbers, including integers, fractions, rational numbers, irrational numbers and so on. Geometry is a subject that studies the shape and size of space, including plane geometry and solid geometry.

3. Application and value of mathematics: Mathematics is widely used in natural science, social science, engineering and other fields. For example, in physics, mathematics is used to describe the laws and properties of natural phenomena; In economics, mathematics is used to analyze data and predict market trends; In computer science, mathematics is used to study and design algorithms and data structures.