Integer: Positive integers, 0 and negative integers are collectively called integers.
Scores: Positive scores and negative scores are collectively called scores.
Rational Numbers: Integers and fractions are collectively called rational numbers.
Reciprocal: Positive and negative numbers are opposites.
Reciprocal: a number x multiplied by it is 1 and recorded as 1/x, where x! =0
Irrational Numbers: Infinitely circulating decimals are called irrational numbers, including positive and negative irrational numbers. For example, the square root or cube root of many numbers are irrational numbers. For example, 2 –√, 3 –√ 32, 33.
Real number: rational number+irrational number are collectively called real numbers. Include positive real numbers+negative real numbers. The horizontal axis on the corresponding plane.
Imaginary number: even numbers with negative exponential power are defined as pure imaginary numbers (a+bxi numbers, where a and b are real numbers, b≠0, i? =- 1。 A is the real part and b is the imaginary part), and the imaginary number has no arithmetic root. The longitudinal axis on the corresponding plane.
Complex number: real number+imaginary number is called complex number.
02, junior high school mathematics-algebraic expression multiplication
1, polynomial multiplication
Multiply polynomials by multiplying each term of one polynomial by each term of another polynomial, and then add the products.
2. Variance formula
Square difference formula: the product of the sum of two numbers and the difference of two numbers is equal to the square difference of these two numbers.
3. Sum of squares formula
The square formula of sum: the square of the sum (or difference) of two numbers is equal to the sum of their squares, plus (or minus) twice their product.
03, junior high school mathematics-a quadratic equation.
Get two unequal real roots: x 1=? b+b2？ 4ac√2a，x2=？ b？ b2？ 4ac√2a？ Get two unequal real roots:
04, junior high school mathematics-polynomial
Polynomials are algebraic expressions obtained by finite addition, subtraction, multiplication and power operations on natural numbers with variables called unknowns and constants called coefficients.
Monomial: Polynomials containing only one term are called monomial constant terms: one term contains no unknowns.
Application of 1, polynomial addition, subtraction, multiplication and division 2, polynomial matrix multiplication and division 3, factorization 4, polynomial equation and function