- #1
Chromosom
- 15
- 0
Homework Statement
I have got a question concerning the following function:
[tex]f(x,y)=\log\left(x^2+y^2\right)[/tex]
Partial derivatives are:
[tex]\frac{\partial^2f}{\partial x^2}=\frac{y^2-x^2}{\left(x^2+y^2\right)^2}[/tex]
and
[tex]\frac{\partial^2f}{\partial y^2}=\frac{x^2-y^2}{\left(x^2+y^2\right)^2}[/tex]
The conclusion is that the following equation is right:
[tex]\frac{\partial^2f}{\partial x^2}=-\frac{\partial^2f}{\partial y^2}[/tex]
But I can not understand, how can it be possible. The role of x and y variables are exactly the same, then why derivatives are not the same?
Sorry for my English - it is my second language. I am from Poland.