Proving Multivariable Limit: f(x, y) → 0

In summary, to prove that lim(x,y)→(0,0) f(x, y) = 0, we can start by using the definition of a limit and fixing epsilon, then finding the corresponding delta in terms of epsilon. This will help us show that for any given epsilon, there exists a delta such that the distance between f(x,y) and 0 is less than epsilon whenever the distance between (x,y) and (0,0) is less than delta.
  • #1
karens
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Homework Statement


Consider that f(x, y) = [sin^2(x − y)] / [|x| + |y|].
Using this, prove: lim(x,y)→(0,0) f(x, y) = 0


Homework Equations



Definition of a limit, etc.

The Attempt at a Solution


I don't know how to start... I've been trying to self-teach limits for a while and Don't know how to do it with the absolute values and two variables. Help is much needed.
 
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  • #2
Start with the definition of a limit:

[tex] \forall \epsilon > 0\ \ \ \exists \delta > 0[/tex] such that [tex]||f(x,y) - f(x_0,y_0)|| < \epsilon[/tex] whenever [tex] ||(x,y) - (x_0,y_0)|| < \delta[/tex].

One way to think of it is to start by fixing epsilon and then finding what delta must be (in terms of epsilon).
 

FAQ: Proving Multivariable Limit: f(x, y) → 0

1. What is a multivariable limit?

A multivariable limit is a mathematical concept that describes the behavior of a function as the independent variables approach a specific point. It is used to determine the value of a function at a given point by examining its behavior near that point.

2. How is a multivariable limit different from a single variable limit?

A multivariable limit involves multiple independent variables, while a single variable limit only has one. This makes multivariable limits more complex and requires a different approach to solve.

3. What does it mean for a multivariable limit to approach 0?

When a multivariable limit approaches 0, it means that the function's value approaches 0 as the independent variables get closer to a specific point. This does not necessarily mean that the function is equal to 0 at that point, but rather that it gets arbitrarily close to 0.

4. How do you prove a multivariable limit is equal to 0?

To prove that a multivariable limit is equal to 0, you must show that the function approaches 0 as the independent variables approach the specified point. This can be done using a variety of methods, such as evaluating the limit algebraically or graphically, or using the epsilon-delta definition of a limit.

5. Why is proving a multivariable limit important in scientific research?

Proving multivariable limits is important in scientific research because it allows us to better understand the behavior of complex functions and make predictions about their values. This is particularly useful in fields such as physics and engineering, where multiple variables can affect the outcome of a system. It also helps us to accurately model and predict real-world phenomena.

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