(4)
which is free from the arbitrary constants a and b and hence this the required differential
equation © NCERT
not to be republished
DIFFERENTIAL EQUATIONS
389
Example 6 Form the differential equation
representing the family of ellipses having foci on
x-axis and centre at the origin Solution We know that the equation of said family
of ellipses (see Fig 9 3) is
2
2
2
2
x
y
a
+b
 = 1