5.1. - , , () - .
F (x, y, y ¢, y ¢) = 0
, ²,
y ¢ =
f (x, y, y ¢). (5.1)
5.2. -
= j(, 1, 2),
1 2 ,
( 0) = 0
~
¢( 0) = 0¢,
~
1
2,
= j(, ~ , ~)
1 2
- , .
5.3. , 1 2, - .
5.4. (5.1) :
f (x, y, y ¢)
¢ ,
= 0,
= 0,
¢ = 0¢,
= (),
( 0) = 0,
¢( 0) = 0¢.
5.5. ,
.
I .
¢ =
f (x).
:
¢ = dy ¢,
dx
y ¢ = ò f (x) dx + c 1,
¢ = dy,
y = ò (ò f (x) dx) dx + c x + c.
dx 1 2
II . ():
¢ =
f (x, y ¢).
¢ = z (x).
¢ = z ¢,
z ():
z ¢ =
f (x, z).
III . :
¢ =
f (, y ¢).
¢ = z ().
¢ = dz
dy = dz z,
dy dx
dy
z dz =
dy
f (y, z).