What is the implicit differentiation of

Question

cos(x-y)=xy?

and if you could find the tangent line at (0,pi)

Answer 1

The function is  cos(x - y) = xy .

Differentiate the function with respect to x .

So the implicit differentiation of cos(x - y) = xy is  

The given point (0,pi) is doesn't satisfy in the function cos(x - y) = xy .

So  tangent is doesn't exist at (0,pi) .