y = 
2
2
a
−x
x ∈ (–a, a) :
x + y dy
dx  = 0 (y ≠ 0)
11 The number of arbitrary constants in the general solution of a differential equation
of fourth order are:
(A) 0
(B) 2
(C) 3
(D) 4
12 The number of arbitrary constants in the particular solution of a differential equation
of third order are:
(A) 3
(B) 2
(C) 1
(D) 0
9 4  Formation of a Differential Equation whose General Solution is given
We know that the equation
x2 + y2 + 2x – 4y + 4 = 0