# Sketch level sets

1. Sep 19, 2013

### 939

1. The problem statement, all variables and given/known data

I am very uncomfortable with the concept of "level sets" and don't quite get what it means.

2. Relevant equations

y = 2(x1)^2 - (x1)(x2) + 2(x2)^2

y = 2x1^(1/2) * x2^(1/2)

3. The attempt at a solution

I'm not even sure where to start... Can anyone please give me some basic knowledge of how to approach these problems?

2. Sep 19, 2013

### Ray Vickson

A level set of f(x1,x2) is the curve f(x1,x2) = constant. If z = f(x1,x2) describes a hill or mountain, a level set of f would be a path of constant elevation. That's all!

3. Sep 19, 2013

### 939

Thanks...

So in the top example above,

2(x1)^2 - (x1)(x2) + 2(x2)^2 = C?

What I'm confused about also is how I would graph it...

4. Sep 19, 2013

### Ray Vickson

For a given numerical value of C, the equation describes some type of curve; you need to figure out what that curve is, and draw it. Surely you must have done problems like that in the past!

5. Sep 19, 2013

### 939

Thanks... The only thing I don't get is figuring out what the curve is when there is always two xs, i.e. y = ((x1)^(2))*((x2)^(2))... Do you use algebra to put it into a form you can understand better?

Sorry for the newb questions...

Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted