A change in one number causes a change in another;

A change in one thing causes a change in another;

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The first variable is the independent variable;

The following variables are dependent variables. The "cause" here is the cause of cause, not the cause of cause. Otherwise it will cause misunderstanding!

The meaning of dependent variable is actually the meaning of "dependent variable", which means that it should be combined, combined, corresponding and responded.

Function refers to the relationship between variables, and the two quantities are linked by mathematical expressions.

The expression of the function can't be finished here, so you can write a gobbledygook.

What I learned in junior high school:

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 Commonwealth countries and the United States learn much more than students in China. Junior high school students and senior high school students in our country learn less knowledge. We can't stand it. We think we've learned a lot, but we're not. The landlord can check it online. O-Level is a junior high school graduation exam in the Commonwealth. The calculus they got was much deeper than the calculus we learned in high school. The above functions are only the simplest functions for AP students in the Commonwealth and the United States.

The above is for reference only.