, .
. e 1, e 2, e 3 R 3 , e 1, e 2, e 3 - . a ,
= x1 e 1 + x2 e 2 + x3 e 3, (1.1)
x1, x2, x3 (1.1) a e 1, e 2, e 3 a (x1, x2, x3).
. e1,e2, e3 , , x1, x2, x3 - . i, j, k.
, R 3 {0, i, j, k }.
. b c, :
1. c , a b, . .
c = |a||b| sin (a ^ b).
2. c a b.
3. a, b c, , .
c c = [ ab ]
c = a × b.
a b , sin(a^b) = 0 [ ab ] = 0, , [ aa ] = 0. : [ ij ]= k, [ jk ] = i, [ ki ]= j.
a b i, j, k a (a1, a2, a3), b (b1, b2, b3),
20
, . .
. b c, a b c.
: , : . : . , , .
, , , , :
,
1.
: (λa)bc = λ(abc).
b×c = e -
,
(λa)bc = (λa)(b×c) = (λa)e = λ(ae) = λ
|
|
a(b×c)= λ(abc). I
2. (a1 + a2)bc =
= a1bc + a2bc.
b×c = e ,
(a1 + a2)bc = (a1 + a2)(b×c) = (a1 + a2)e = a1e + a2e =
= a1(b×c) + a2(b×c) = a1bc + a2bc. I
1 2
.
, ..
a(λb)c = λ(abc), ab(λc) = λ(abc),
a(b1 + b2)c = ab1c + ab2c, ab(c1 + c2) = abc1 + abc2, -
.