Learn what a function is and how to evaluate functions with this comprehensive video tutorial from Khan Academy.

A calculus-based justification is when we explain a property of a function f based on its derivative f'. See a good example (and a few wrong ones) for how to do this when explaining why a function increases.

In the first inverse function video, I talked about how a function and their inverse-- they are the reflection over the line y equals x. So where's the line y equals x here?

Intuitively, a function is continuous if you can draw it without picking up your pencil, it's a single connected line. If you have to pick up your pencil to accommodate a hole or a jump, then the function …

When x is 0, y is 1. When x is 2, y is 3. You might say, well, what was the whole point of using the function notation here to say f of x is equal to x plus 1? The whole point is to think in these more …

Discover how to determine if a function is continuous on all real numbers by examining two examples: eˣ and √x. Generally, common functions exhibit continuity within their domain.

Learn how to build a mapping diagram for a finite function, and how to use this diagram to determine if the function is invertible. An invertible function has a one-to-one mapping between its domain and …

Learn about evaluating functions with step-by-step examples and practice exercises on Khan Academy.

What if we told you that given the equation of the function, you can find all of its maximum and minimum points? Well, it's true! This process is called the first derivative test. Let's unpack it in a way that …

Learn how to understand and use function notation through this video tutorial from Khan Academy.