(6)
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DIFFERENTIAL EQUATIONS
381
2
d y2
y
dx
+
 = 0 (7)
3
3
2
2
3
2
d y
d y
x
dx
dx
⎛
⎞
⎛
⎞
+
⎜
⎟
⎜
⎟
⎝
⎠
⎝
⎠
= 0 (8)
The equations (6), (7) and (8) involve the highest derivative of first, second and
third order respectively Therefore, the order of these equations are 1, 2 and 3 respectively