.
, . u x, y, z,
u = f (x,y,z). (5.5)
(5.5) du, dx, dy, dz, . D u, D x,D y,D z, .
D u D x,D y,D z, . , n , n :
(i = 1, 2, , n)
, n:
,
.
(n ¥) , (5.4) (5.3), : , , , , .
(5.6)
, , .
.
1. u x, y, z:
u = x + y + z.
=1, =1, =1.
= + + .
2. u x y:
u = x - y.
=1, =-1.
= + .
3. u :
u = k× x,
k . = k, = k 2×
mu = k× mx.
4. u x, y, z, :
u = k 1 x + k 2 y + k 3 z ,
ki . = k 1, = k 2, = k 3.
.
.
1. , d =124,16 n=216´, md = 0,06 , m n = 1´.
h = d tgν.
d n:
, .
(5.6)
,
3438¢ - . mh =0,036..
2. (. 9.2)
h = a - b.
ma = mb = 2 .
= 2,8
3. (. 9.4).
f b= b1+ b2+ ¼+ b n -180(n -2),
b i (i = 1, 2, ¼, n) n .
- b i.
mf = = ,
m 1 = m 2 =¼ = mn = m . m = 0,5¢.
(f b) (f b)=2 mf.
(f b) = 1¢ .
|
|
. : l 1, l 2, , ln.
. (5.7)
(5.1) li= + Δ i (i = 1, 2, n).
= X - .
(5.2) , , , , , L . .
. l 1, l 2, , ln
m 1 = m 2 = ¼ = mn = m
M .
(5.7) :
L = .
(5.6)
(5.8)
(5.8) , . , 2 , 4 .
. l1, l2, , ln :
1. L
.
2. v i
(i = 1, 2, , n)
, .
3. :
.
m - .
4.
.