, z = f(x, y) 0(0, 0), f(x0, y0) > f(x, y) , f(x0, y0) < f(x, y) , 0 . . : = 0 + D = 0 + D, f( + D, + D) f(0, 0) = Df. Df > 0 , f(x, y) 0. Df < 0 , f(x, y) 0.
. :
z = f(x, y) = 0, = 0, z , .
, z = f(x, y) 0(0,0) , z = f(0, ) z = f(, 0) , , . , , , ( ) . , zx` = 0 z` = 0 . :
, 0(0, 0), 0 , :
, D > 0, A < 0 (C < 0)
, D > 0, A > 0 (C > 0)
, D < 0
D = 0 , .
(4.12), :
2.1. :
1) ;
2) 1 3 ;
3) 2 ;
4) .
2.2. , :
1) ; 3) ;
2) ; 4) .
2.3. =
1) ; 2) ; 3) ; 4) .
2.4. ;
1) ; 2) ; 3) 0; 4) .
2.5. ; , (1; 2; ) :
1) ;
2) ;
3) .
2.6. ; , N(1; 2; 1) :
1) ;
2) ;
3) .
2.7. (1; 1) (6; 8) :
1) ; 2) ; 3) ; 4) .
2.8. (2; 1; 1) :
1) ; 3) ;
2) ; 4) .
2.9. , , :
1) max; (1; 1); 3) max; (0; 0);
2) min; (1; 1); 4) min; (0; 0).
2.10. ; ; . z :
1) min; 3) ;
2) max; 4) .
.
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.
. .
f(x) - f `(x). F(x), - f(x).
F(x) f(x) [a, b], F`(x) = f(x).
: [F(x) + C]` = f(x). F(x) f(x), F(x) + C f(x).
F() f(x), F(x) + C f(x)
ò f(x)dx = F(x) + C (5.1),
. f(x) , f(x)dx , ò .
, , .
f(x) [a, b], ( ). ( ).
f(x) .
, , .
:
1. , .. F`(x) = f(x), (òf(x)dx)` = f(x) (5.2).
2. , .. d(òf(x)dx) = f(x)dx (5.3).
3. òF(x) dx = F(x) + C (5.4).
, :
4. : ò[f1(x) + f2(x)]dx = òf1(x)dx + òf2(x)dx (5.5).
5. , .. = const, òaf(x)dx = aòf(x)dx (5.6).
6. òf(x)dx = F(x) + C u = j(x), òf(u)du = F(u) + C (5.7).
(5.2) (5.7) .
a ¹ 1 (5.8) | (5.15) |
(5.9) | (5.16) |
(5.10) | (5.16`) |
(5.11) | (5.17) |
(5.12) | (5.17`) |
(5.13) | (5.18) |
(5.14) | (5.18`) |
, .
(5.19) (5.20)
, , . , . : òf(x)dx , x = j(t) (j(t) , ). dx = j`(t)dt òf(x)dx = òf(j(t))j`(t)dt. , t ( ). j(t) , .
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: . = t, dx = dt, t=x/a.. = = [ (5.17)] = = .. (5.17`).
t = y(x).
[cosx = t; sinxdx = dt] = .
. u v , d(uv) = vdu + udv , ,
uv = òvdu + òudv òudv = uv òvdu (5.22).
.
" " - u dv, , òvdu , .
: òdx =? u = x exdx = dv, du = dx v = ex òdx = òdx = + C.
, v dv .
. ( , ).
, - . (m ³ n), , .
: ; ; ; , k ³ 2, 1, 2, 3 4 . , .
1. (5.23)
2. (5.24)
3. . d(x2 + nx + q) = (2x + n)dx ,
(5.25)
.
( ).
1. = , .. f(x) = ( )f1(x) f1() ¹ 0, , , , F1(x) , ( )1f1(x).
1. f(x) = (x2 + nx + q) mj1(x), j1() x2 + nx + q, : , () , (x2 + nx + q) m1j(x). , , f(x). .. f(x) = ( )a( b)b (x2 + nx + q)m (x2 + lx + s)n, :
, 1, , , 1, , . , . , , 1, ,, 1,
: . , 2 + 2 = ( 2) + 1( + 1)( 2)
+ 2( + 1)2( 2) + ( +1)3 2 + 2 = (2 + )3 + (1 + 3)2 + ( 1 32 +
+ 3) + (2 21 22 + ). 3, 2, , 0 ( )
: = 1, 1 = 1/3, 2 = 2/9, = 2/9
: .
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, , , , .
: