Evaluating Partial Derivative of g w.r.t. Theta at (2*sqrt(2),pi/4)

[snoggerT]

use chain rule to evaluate partial derivative of g with respect to theta at (r,[theta])=(2*sqrt(2),pi/4), where g(x,y) = 1/(x+y^2), x=rsin[theta] and y=rcos[theta]


r^2=x^2+y^2 and tan[theta]=y/x

The Attempt at a Solution

I understand how to use the chain rule for partial derivatives, but I can't seem to figure out any of the problems that use polar coordinates. please help.

 

[m_s_a]

use
x=rcos(theta)
y=rsin(theta)

 

[snoggerT]

use
x=rcos(theta)
y=rsin(theta)

- so for every x/y in the equation I get, plug in the polar coordinate for them?