# Thread: Interesting partial derivative question

1. ## Interesting partial derivative question

Hey Friends,

Take a look at the following function:

f(x,y,z)=0 if x<y
f(x,y,z)=z if x>=y

What are the partial derivatives of the function, with respect to x and y, separately? i.e., what is df/dx and df/dy

2. Looks like $\frac{\partial f}{\parital x} = \frac{\partial f}{\parital y} = 0$ but why?