Calculus AP need help!
posted by stacey .
its difficulty problem.
find dy/dx by implicit differentiation
1.4 cos x sin y = 1
2.tan(x/y)= x+y

1.) 4 cos x sin y = 1
2.) tan(x/y)= x+y 
using product rule and chain rule,
4 (sinx)(siny) + 4(cosx)(cosy y') = 0
y' = sinx*siny / cosx*cosy
= tanx * tany

sec^2(x/y)*(1/y  x/y^2 * y') = 1 + y'
y*sec^2(x/y)  y^2
 = y'
y^2 + x*sec^2(x/y)