# Function to find

1. Feb 7, 2009

### Heimdall

Hi,

I'm looking for a function f(x,y) which has the following properties :

$$\frac{-\partial f}{\partial x}$$ tends to 0 when x or y tends to $$\pm \infty$$, odd in the x direction, and even in the y direction.

something that has a shape like $$exp(-(x^2 + y^2))*tanh(x)$$.

And $$\frac{\partial f}{\partial y}$$ has a shape that looks like $$exp(-(x^2+y^2))$$

I'm looking for f, and not the derivative independantly because I want the divergence of the vector (df/dx, df/dy) to be 0.

can you help me ?
Thanks