# Math Help - finding the derivative

1. ## finding the derivative

$
xy = sin(x^2 + y^2)
$

$
x \cdot y' + y = sin(x^2 + y^2)
$

when i take the derivative of the right side is it:

$
cos(x^2 + y^2) \cdot 2x \cdot 2yy'
$

or
$
cos(x^2 + y^2) \cdot 2x + cos(x^2 + y^2) \cdot 2yy'
$

or none of the above?
thanks

2. ## Re: Derivative

$
cos(x^2 + y^2) \cdot 2x \cdot 2yy'
$