# Calculus 3 extra credit

1. Jun 9, 2005

### ACLerok

Hi i'm having trouble with this extra credit problem i've been given. I am supposed to prove:

dx/dy * dy/dz * dz/dx = -1 (partial derivatives)

I think i'm supposed to use the chain rule but not sure. Can anyone help me out?

2. Jun 10, 2005

### Andrew Mason

This is not the complete statement of the problem. One has to know what the function is. Please provide the complete problem as given to you.

AM

3. Jun 10, 2005

### ACLerok

sorry nope.. it's all i was given.

4. Jun 10, 2005

### Hurkyl

Staff Emeritus
It's true in general. matt grime likes to bring it up now and then!

How did trying the chain rule go? (I assume you tried it, since you thought it would be a good idea) How did you set up the problem?

5. Jun 12, 2005

### ACLerok

i figured if you treat them as quotients you can 'multiply' by dy/dx, dz/dy, and dx/dz to cancel them out but that wouldn't work.. I only said the chain rule cause my TA gave us that hint

6. Jun 13, 2005

### matt grime

firstly, it must be assumed f(x,y,z)=0 implicitly defines x as a function of y and z and y as a function of x and z and z as a function of x and y.

then just use the usual rules of implicit differentiation and partial derivatives.