4.1. , - () ¢, . .
¢ + () × = q (x),
() q (x) .
q (x) º 0, -
.
4.2. -
.
¢ + () × = 0,
= × -ò () dx.
,
= () × -ò () dx, () .
.
4.3. .
= u (x) × v (x),
u (x) v (x) .
¢ = u ¢ × v + u × v ¢
,
u ¢ × v + u × v ¢ + p (x) × u × v = q (x),
u ¢ × v + u (p (x) × v + v ¢) = q (x).
v (x) -
v ¢ + p (x) × v = 0,
u (x) ,
u ¢ × v = q (x).
u (x) v (x),
= u (x) × v(x).
4.4. - () ¢. :
¢ + () × = q ().
4.5.
¢ + p (x) = q (x) × n, n ¹ 0, n ¹ 1.
z = y 1- n
z ¢
1 - n
+ p (x) × z = q (x).
.
y = u (x) × v (x)