.
, , , , :
.
.. , d(x,y,z) V, :
.
2.2
.
V ( n) f(x,y,z).
V n ( ) Dni (i = 1,2,...,n). (xi, hi, Vi), f(xi, hi, Vi)
f(x,y,z) V.
.
s , Vi , f(x,y,z) V òòòV f (x,y,z)dn.
dn
dn = dx dy dz.
,
f(x,y,z) V.
V f(x,y,z).
2.3
1. V , :
2-
.
.
.
2. :
...
.
.
3. V V1 V2 , ,
.
.
.
4. V f(x,y,z) j(x,y,z) f(x,y,z) £ j(x,y,z),
,
.. .
5. V f(x,y,z) m £ f(x,y,z) £ M,
,
n - V.
6. :
,
V.
2.4
, .
1. V , :
£ x £ b; c £ y £ d, e £ z £ h (, D: £ x £ b; c £ y £ d).
|
|
, f(x,y,z) ,
.
(, ) F(x,y).
D :
. (2.1)
òòD(eòh f dz)dxdy ; :
.
.. òòD (,)dxdy = aòb dx còd (x,y)dy, (2.1) :
. (2.2)
, , ; (2.2) ( ) , .. 3- .
:
.
2. V ; z1 = z1(x,y), z2 = z2(x,y), ( ), V D.
f(x,y,z) V.
.
V , , , 2- .
D, z1(x,y) z2(x,y):
z 2(x,y) ³ z1 (x,y).
D 1 = 1(), 2 = 2(),
£ £ b.
: 1 = 1(); : 2 = 2().
Oz. f(x,y,z) V , Oz (; ) Î D.
z z1(,) z2(x,y),
z1(,) V;
z2(x,y)- V.
, .(;), F(x,y):
.
( z).
F(x,y) D.
òòòV f(x,y,z)dn , F(x,y) , .(;) D, .. òòD F(x,y,)dxdy.
, :
= , , òòD =
(2.3)
.
, .
3. V , , .
2.4.1.
, V y2 + az2 = bx (a > 0, b > 0), , = .
.
|
|
2.5.
V V* :
, ,
:
J¹0 V*,
(2.4)
2.6
.
, (x;y;z) r, q, z , r,q, z .
, , :
x = r cos q, y = r sin q, z = z (r ³ q, 0 £ q £ 2p, - ¥ < z < + ¥).
.
V Vi :
1) r = r0(const) 2 + 2 = r0, Oz;
2) q = q0 (const) , Oz;
3) z = z0 , .
Vi (.2.4).
dn = S h (S = dxdy = rdrdq; h = dz).
dn = rdrdqdz.
òòòV f(x,y,z) dn .
1) f(x,y,z) x,y,z (2.1) 2) dn, rdrdqdz.
. (2.5)
, .
(2.5) (2.4) :
2.6.1
, V- , x2 + y2 = R2, z = 0, z = 1,y = x, y = I .
2.6. 2
, V , z = 1 x2 y2, 2 + 2 = 1 z = 1.
I 1,31.
2.7.
. ( x,y,z) 1) r (0 £ r < +¥), 2) j OZ (0 £ j £ p) 3) q , (0 £ q £ p).
x, y, z .
(.2.7)
Z = ÷ ÷ cos j = r cos j; ,
=÷ 1÷ cos q; = ÷ 1÷ sin q,
÷ 1÷ = ÷ ÷ sin j = r sinj.
, ,
:
(r ³ 0; 0 £ j £ p; 0 £ q £ 2p).
2.8.
V :
1) r = r0 (const) x2 + y2 + z2 = r02 c (0 £ r0 < +¥);
2) j = j0 (const) - ( );
3) q = q0 (const)- , Oz.
Vi dr, rdj, r sinj dq.
(: r, , ).
|
|
:
.
(2.6)
(2.6) (2.4). :
(. 3 )=
=
sin j > 0, .. 0 < j < p.
.
, V- .
, . 1) , 2) .
, .
2.7.1
, x2 +y2 + z2 £ R2,
.
.
2.9
2.9.1
f(x,y,z) º 1 V.
= n;
. (2.7)
2.9.1.
, x2 + y2 + z2 = 4 3z = x2 + y2.
(.).
2.10.
, , V,
, (2.8)
d(x,y,z) .
.
, z = 4, z .
2.11.
.
.
, , .
V , () , d = d(x,y,z).
Vi Dni (i = 1, 2,..., n)
Vi (xi, hi, Vi).
Vi , (xi, hi, Vi), :
.
(xi, hi, Vi) Dmi.
(xi, hi, Vi) Vi :
.
:
.
, , :
.
z yOz:
.
.
V , :
,
m :
,
(2.9)
.
d = const, :
, (2.10)
n- .
2.10.1
, z = x2 + y2, 2 + 2 = 4, z = 0.
(.).
xOz yOz, , Oz,
xc = yc = 0.
,
. (0; 0; 4/3).
2.12
|
|
V, d = d(x,y,z). .
Vi Dni, :
.
.
.
, , :
. (2.11)
:
. (2.12)
2.11.1
(d = 1) 1) 2) , , .
.
: y2 + z2 = a2.
1. = Iz.
= ; = r cosq
.
2. = Ix.
.
.
.
1. , . :
1.1
1.2
1.3