Meaning of function, independent variable, dependent variable (math)

A change in one number causes a change in another number;

A change in one thing causes a change in another thing;

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The quantity that changes first is the Independent Variable;

The quantity that follows is the Dependent Variable. The word "cause" here is "consequent", not "because". Otherwise, it will cause misunderstanding!

The meaning of "dependent variable" is actually the meaning of "response variable", which means to be in harmony with, to fit, to correspond to, to respond to.

Function (Function) is the relationship between the variables (Relation), is a mathematical expression (Expression) will be two quantities connected.

The expression of the function, it is not enough to say here, you can write a book of days.

From junior high:

y = kx + c

y = ax^2 + bx + c

y = sinx

y = cosx

y = tanx

y = cotx

y = e^x

y = lnx

y = lgx

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Note: AP students in the United States, in a Commonwealth country, learn much more than at home. Our domestic middle and high school students learn less. We can't stand to hear, think we learn a lot of very deep, in fact, not. O-Level is the Commonwealth's examination for junior high school graduates. The calculus that people take is much deeper than the calculus that our high school students learn. The functions above are just a little bit of the simplest functions in the eyes of Commonwealth and American AP students.

The above is for reference only.