# Math Help - partial differentiation!

1. ## partial differentiation!

if $x=z^2 \arctan(\frac{y}{z}) find \frac{d^2x}{dzdy}$

have attempted the problem above and here is what i got;

$\frac{3z^4+9z^2y^2}{(z^2+y^2)^2}$

pls see to this solution if am in order, thanks.

2. ## Re: partial differentiation!

Shouldn't it be :

${\frac {{z}^{2} \left( {z}^{2}+3\,{y}^{2} \right) }{ \left( {z}^{2}+{y}^{2} \right) ^{2}}}$