Question
Solve the following initial value problem:
(1 + x y) y dx + (1 – x y) x dy = 0, y (1) = 1.
Solution
The given differential equation is
(1 + x y) y dx + (1 – x y) x dy = 0
or
or
...(1)
Let I =
Put x y = t so that x dy + y dx = dt

from (1),
Now


which is required solution.
(1 + x y) y dx + (1 – x y) x dy = 0
or

or


Let I =

Put x y = t so that x dy + y dx = dt



Now



which is required solution.