# Is this differential system of equations *coupled*?

1. Sep 15, 2011

### asgard

I am struggling with whether or not to define the following system as coupled:
Using LaTeX (reload if it doesn't display properly)

$\ddot{x}+A*x=0$

$\ddot{y}+A*y=0$

$\ddot{z}+A*z=0$​

where A is a known constant equal to $A=\sqrt{x^2+y^2+z^2}$

So, what do you think?

Last edited: Sep 15, 2011
2. Sep 15, 2011

### LCKurtz

Yes, it is a coupled system. Even if A is constant so the solution is apparently restricted to a sphere, still the value of x depends on y and z. I don't 100% guarantee this answer though.

3. Sep 25, 2011

### HallsofIvy

Staff Emeritus
Yes, these equations are coupled.