2  Basic Concepts
We are already familiar with the equations of the type:
x2 – 3x + 3 = 0 (1)
sin x + cos x = 0 (2)
x + y = 7 (3)
Chapter 9
DIFFERENTIAL  EQUATIONS
Henri Poincare
(1854-1912 )
© NCERT
not to be republished
MATHEMATICS
380
Let us consider the equation:
xdy
dx +y
 = 0