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What is a function? (video) | Functions | Khan Academy
A function-- and I'm going to speak about it in very abstract terms right now-- is something that will take an input, and it'll munch on that input, it'll look at that input, it will do something to that input.
Functions (video) | Function definitions | Khan Academy
Our function definition is now complete, but a function definition just defines how to perform a task. To actually perform that task, we still need to call the function.
什么是函数？ (视频) | 计算函数 | 可汗学院
一个函数——这个名词有点抽象 函数是这样一种东西： 它接受一个输入，然后分析这个输入 观察这个输入 以及处理这个输入 然后根据这个输入的具体情况给出一个输出 我来举个例子 比如有一个f (x) 这 …
Checking if a table represents a function (video) | Khan Academy
Sal determines if y is a function of x from looking at a table. Created by Sal Khan.
Khan Academy | Khan Academy
Ups. Algo salió mal. Por favor inténtalo otra vez. Oh no, parece que encontramos un error. Necesitas actualiza. Si este problema persiste, avísanos.
Worked example: domain & range of piecewise linear functions
Finding the domain and range of a piecewise function where each segment is linear.
Evaluating discrete functions (video) | Khan Academy
Given the graph of a discrete function, Sal shows how to evaluate the function for a few different values.
Worked example: matching an input to a function's output (equation)
Saying "f (x)" instead of "y" highlights the fact that you put a value for x into the function and get out a value for y. The function describes how y varies with x.
Limits from graphs: limit isn't equal to the function's value
In order to determine the function that corresponds to the graph depicted in the video, we must first observe that it intersects the x axis three times, indicating that it has three x intercepts.