1. ## Partial Derivative Question

Can't seem to figure it out.

$\frac{d^{2}z}{dx^2}.......... z=arctan(\frac{y}{x})$

Thanks. I did not know how to make a tan inverse in Latex.

2. Originally Posted by Gotovina7
Can't seem to figure it out.

$\frac{d^{2}z}{dx^2}.......... z=arctan(\frac{y}{x})$

Thanks. I did not know how to make a tan inverse in Latex.

p.s the code is tan^{-1}

$\frac{\partial z}{\partial x}=\frac{1}{1+\left( \frac{y}{x} \right)^2}\cdot \left( -\frac{y}{x^2}\right)=\frac{-y}{x^2+y^2}$

taking one more gives

$\frac{\partial ^2 z}{\partial x^2}=\frac{2xy}{(x^2+y^2)^2}$