# Write a math function

How to Write Functions in Math By Casey Woods; Updated April 25, You can graph circles, ellipses, lines and parabolas and represent all these by equations in math. However, not all these equations are functions. In math, a function is an equation with only one output for each input. Visualizing scalar-valued functions Video transcript - [Voiceover] Hello and welcome to multivariable calculus. So I think I should probably start off by addressing the elephant in the living room here.

I am, sadly, not Sal, but I'm still gonna teach you some math. My name is Grant. I'm pretty much a math enthusiast. I enjoy making animations of things when applicable, and boy, is that applicable when it comes to multivariable calculus. So, the first thing we gotta get straight is what is this word multivariable that separates calculus, as we know it, from the new topic that you're about to study? Well, I could say it's all about multivariable functions, that doesn't really answer anything because what's a multivariable function?

Write a math function basically, the kinds of functions that we're used to dealing with, in the old world, in the ordinary calculus world, will have a single input, some kind of number as their input, and then the output is just a single number. And you would call this a single variable function.

Basically because that guy there is the single variable. So then a multivariable function is something that handles multiple variables. So, you know, it's common to write it as x, y, it doesn't really matter what letters to use, and it could be, you know, x, y, z, x one, x two, x three, a whole bunch of things, but just to get started, we often think just two variables and this will output something that depends on both of those.

Commonly it will output just a number, so you might imagine a number that depends on x and y in some way, like, x squared plus y, but it could also output a vector, right? So you could also imagine something that's got multivariable input, f of x, y, and it outputs something that also has multiple variables, like, I mean I'm just making stuff up here, three x and, you know, two y.

And, this isn't set in stone, but the convention is to usually think if there's multiple numbers that go into the output, think of it as a vector, if there's multiple numbers that go into the input, just kind of write them, write them more sideways like this, and think of them as a point in space.

Because, I mean when you look at something like this, and you've got an x and you've got a y, you could think about those as two separate numbers. You know, here's your number line with the point x on it somewhere, maybe that's five, maybe that's three, it doesn't really matter.

And then you've got another number line and it's y, and you could think of them as separate entities. But, it would probably be more accurate to call it multidimensional calculus, because, really, instead of thinking of, you know, x and y as separate entities, whenever you see two things like that you're gonna be thinking about the x y plane.

And thinking about just a single point. And you'd think of this as a function that takes a point to a number, or a point to a vector. And a lot of people, when they start teaching multivariable calculus, they just jump into the calculus, and there's lots of fun things, partial derivatives, gradients, good stuff that you'll learn.

But I think first of all, I want to spend a couple videos just talking about the different ways we visualize the different types of multivariable functions.

So, as a sneak peak, I'm just gonna go through a couple of them really quickly right now, just so you kind of whet your appetite and see what I'm getting at, but the next few videos are going to go through them in much, much more detail.

So, first of all, graphs.An interactive turorial on the graph of the general tangent function and its properties such as period, phase shift and asymptotes. Obtaining Equations from Piecewise Function Graphs.

You may be asked to write a piecewise function, given a graph. Now that we know what piecewise functions are all about, it’s not that bad! Common Core Math: 8.F.A.1, urbanagricultureinitiative.comA.1 Problem For a given input value x x x x, the function f f f f outputs a value y y y y to satisfy the following equation.

While this is a serious limitation, multi-level formulas are not always needed and even when they are needed, proper math symbols still look better than improvised ASCII approximations. Compare: ∀(x, y ∈ A ∪ B; x ≠ y) x² − y² ≥ 0.

## Browser Support

The class Math contains methods for performing basic numeric operations such as the elementary exponential, logarithm, square root, and trigonometric functions.. Unlike some of the numeric methods of class StrictMath, all implementations of the equivalent functions of class Math are not defined to return the bit-for-bit same results.

This relaxation permits better-performing implementations. In math, a function is an equation with only one output for each input. In the case of a circle, one input can give you two outputs - one on each side of the circle.

Thus, the equation for a circle is not a function and you cannot write it in function form.

Functions | Algebra I | Math | Khan Academy