Question

Find a particular solution of the differential equation (x – y) (dx + dy) = dx – dy, given that y = -1, when x = 0. (Hint: put x – y = t)

Answer 1

x + y = log (x – y) + C 

when x = 0, y = -1 

0 – 1 = log(0 + 1) + C 

⇒ C = -1

x + y = log (x – y) – 1.