Лекции по векторному и тензорному анализу. Лосик М.В. - 4 стр.

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|~a(t) ~a|
t ~a =
lim
tt
0
~a(t)
ε > 0 ) ( δ > 0 ) ( t 6= t
0
|t t
0
| < δ) )( |~a(t) ~a| < ε ).
~a(t)( a
x
(t), a
y
(t), a
z
(t) )
t
0
t
0
~a( a
x
, a
y
, a
z
)
~
i,
~
j,
~
k lim
tt
0
~a(t) ~a
lim
tt
0
a
x
(t) lim
tt
0
a
y
(t) lim
tt
0
a
z
(t)
a
x
a
y
a
z
|~a(t) ~a| =
q
(a
x
(t) a
x
)
2
+ (a
y
(t) a
y
)
2
+ (a
z
(t) a
z
)
2
.
|a
x
(t) a
x
|, |a
y
(t) a
y
|, |a
z
(t) a
z
| |~a(t) ~a|.
lim
tt
0
~a(t) ~a
lim
tt
0
a
x
(t) = a
x
lim
tt
0
a
y
(t) = a
y
lim
tt
0
a
z
(t) = a
z
lim
tt
0
a
x
(t) = a
x
lim
tt
0
a
y
(t) = a
y
lim
tt
0
a
z
(t) = a
z
lim
tt
0
~a(t) = ~a
~a(t)
a
z
(t) = a
z
= 0
~a(t)
lim
tt
0
~a(t) = ~a lim
tt
0
|~a(t)| = |~a|
||~a(t)| |~a|| |~a(t) ~a|,
~a(t)
~
b(t) ~c(t)