Question

differtiant with recpect to x​

Answer 1

log(x + y) = logxy + a

log(1/y + 1/x) = a

1/y + 1/x = e^a

diffrenciating with Respect to x we get

-1/y^2 dy/dx - 1/x^2 = 0

dy/dx = - y^2/x^2