Question 1: What is a complex number and when to learn it? Complex number refers to the number a+bi which can be written in the following form, where A and B are real numbers and I is imaginary unit (i.e.-1 root). Cardin, an Italian scholar in Milan, was first introduced in16th century. Through the work of D'Alembert, De Moivre, Euler and Gauss, this concept was gradually accepted by mathematicians. There are many ways to express complex numbers, such as vector representation, triangle representation, exponential representation and so on. It satisfies the properties of four operations. It is the most basic object and tool in complex variable function theory, analytic number theory, Fourier analysis, fractal, fluid mechanics, relativity, quantum mechanics and other disciplines. In addition, plural refers to two or more countable nouns, not singular in English. Imaginary numbers and complex numbers can touch each other in the second year of high school.

Question 2: When did you learn the plural part? If it is a book published by PEP, you should be a sophomore. However, there are several textbooks in China now, some of which may be different, but in terms of learning order, they should all be learned in Grade Two.

Question 3: How many complex numbers do you have to learn in high school? What part is it? How many complex numbers do you have to learn in high school mathematics? 1 which section, the plural number is in the elective material selection 2-2?

2. Elective chapters 2-2 are as follows:

Chapter 1 Derivative and Its Application

Chapter II Reasoning and Proof

Chapter 3: The extension of number system and the introduction of complex numbers.

3. The first chapter mainly introduces the concept of derivative, the function of derivative in function learning, the basic theorem of calculus and so on.

The second chapter mainly introduces reasonable reasoning, deductive reasoning and various proof methods such as analysis, synthesis, reduction to absurdity and mathematical induction.

The third chapter mainly introduces the concept and operation of complex numbers.

Question 4: The plural variation of nouns is composed of _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _. Map-Map 2. Bag-bags read voiced consonants and vowels/z/; Car-cars _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ The word at the end of bus-bus watch-watches is added with-es _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _. (d)add-s reading/iz/ license-licenses _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ Baby-babies _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ Comparison of y monkey-monkeys holidays-holidays: floor: Story-Stories Story 2) nouns ending in o, plural: a. plus s, for example, photo-photos piano-b. plus es, For example, potatos-tomatos-tomatos C. For example, zero-zeros/zeros 3) When nouns ending in f or fe become plural, add s, for example, believe-believe roof-roofssafe-safes. B. Go to F, fe and ves, such as: half knife-half knife leaf-leaf wolf-wife's life-life thief-thief; C. Both can be used, such as handkerchiefs/hankerchieves, irregular change of plural nouns1) child-children foot-foot teeth mouse-mouse man-women Note: It consists of men and women. For example, one Englishman and two Englishmen. But German is not a compound word, so the plural form is German; Bowman is a surname, and its plural is the Bowman family. 2) Simple and complex have the same form and different meanings, such as deer, sheep, fish, Chinese, Japanese plum, gold, yuan, second plum, three wood and four gold, except RMB, horn, extra, USD, GBP, etc. There are plural forms. Such as: A Do>>