Original Function: $(\sin(\pi x)+\cos(\pi y))^2 = 2$
Step1: $2(\pi \cos(\pi x) - \pi \sin(\pi y)\frac{dy}{dx})(\sin(\pi x)+\cos(\pi y))$
Step2: $(2\pi \cos(\pi x)-2\pi \sin(\pi y)\frac{dy}{dx})(\sin(\pi x)+\cos(\pi y)$
... and blah blah blah.. Igot tired of writing this in mathjax..
and my answer came out to be dy/dx = $\cos(\pi x)$ / $\sin(\pi y)$
did I do this right?
Ya you are correct. You can actually use the formula of
$$ dy/dx = -F_x/Fy$$
This might be easier.