Find in each of the following:

sinxy + cos (x + y) = 1

We are given with an equation sinxy + cos(x + y) = 1, we have to find of it, so by differentiating the equation on both sides with respect to x, we get,

cosxy (y + x) – sin(x + y) (1 + ) = 0

[x cosxy – sin(x + y)] = sin(x + y) – y cosxy