, () :
(1) |
, , . , , (1), (), :
Ax 2 + By 2 + Cx + Dy + E = 0; (A 2 + B 2 ≠ 0), | (2) |
.. xy.
(2), .
, (2), A, B, C, D, E .
1. AB ≠ 0, .. A ≠ 0 B ≠ 0 .
:
(2)
(3) |
α = C / 2 A, β = D / 2 B
A (x α)2 + B (y β)2 = H | (4) |
X′O′Y′, XOY ( ). X′O′Y′ . O′ (α, β). M, XOY (,) X′O′Y′ x' = x α y' = y β, (4) X′O′Y′
(5) |
( x' y' x y).
1.1 AB > 0 .
a) A > 0, B > 0, H > 0.
(5)
(6) |
, , a 2 ≥ b 2, 90.
, . .
b) A > 0, B > 0, H = 0.
a 2 = 1 / A, b 2 = 1 / B,
.
O' (0,0).
c) A > 0, B > 0, H < 0.
a 2 = H / A, b 2 = H / B, (5) : .
, .. . .
, AB > 0. .
1.2 AB < 0 .
a) A > 0, B < 0, H > 0.
a 2 = H / A, b 2 = H / B, (5)
(7) |
, , . .
. A > 0, B < 0, H > 0, (5) X′O′Y′ 90,
, x" = y', y" = x'.
b) A > 0, B < 0, H = 0. a 2 = 1 / A, b 2 = 1 / B, : .
: .
, , O' (0,0): . , . , , AB ≠ 0 , AB = 0.
|
|
2 AB = 0 .
2.1 A = 0 (B ≠ 0), C ≠ 0. (2) :
By 2 + Cx + Dy + E = 0.
, :
.
, , , , , : (y β)2 = 2 p (x α). , 1 X ′O′Y′
: (y')2 = 2 px'. :
y 2 = 2 px | (8) |
, y 2 = 2 px, . y 2 = 2 px .
. (8), , p > 0, 180.
. B = 0, D ≠ 0, , , 90.
, (7.2) .
2.2 A = 0 (B ≠ 0), C = 0.
(2) By 2 + Dy + E = 0.
, : . , , , (y β)2 = H, , :
y 2 = H | (9) |
a) H > 0
a 2 = H (9) :
y 2 = a 2 | (10) |
, y = a y = a ( ).
b) H < 0
a 2 = H, (9) : y 2 = a 2. , .. , .
c) H = 0
(9)
y 2 = 0 | (11) |
. (11) (10) (a 2 → 0), , y 2 = 0 .
. B = 0 D = 0 90.
, , Ax 2 + By 2 + Cx + Dy + E = 0 9 (. ).
(AB > 0) | |||
(a > b > 0) | |||
(AB < 0) | |||
( ) | |||
(AB = 0) | |||
y 2 = 2 px (p > 0) | |||
y 2 = b 2 | ( ) | ||
y 2 = b 2 | |||
y 2 = 0 | |||
1-5 , , , |
, , ( ). , . .
|
|
II | (a > b > 0) |
1. O (0,0).
2. .
3. A 1( a,c), A 2(a,0), B 1(0, b), B 2(0, b) (4 ).
4. A 1 A 2 , 2 a; , B 1 B 2 , 2 b (2 b < 2 a). OA 1, OA 2 ; OB 1, OB 2 , a b (a < b). , , , , , .. a, b, 2 a 2 b .
5. , F 1 ( C,0) F 2(C,0), (0 < c < a) . .
: M, , | F 1 M | + | F 2 M | = 2 a, .. , , , , 2 a, (2 a > 2 c).
6. ε = c / a.
, ε < 1. : ε = 0, a = b, .. , 1, , .. .
7. : , , . , ε < 1, , A 1 A 2. .
: M, ,
,
ρ (M, L 1) M F 1( c, 0), ρ (M, L 2) , F 2(c, 0). , (), (), , 1 ( ).
. . , , (), (), , 1, .
8. : , , , , , .. . M, T, MF 1 MF 2 ( α = β).
. 7.1, .
. 7.1
. , (6) Y, . , 1- , .
. , , , , , , , , .
III | (a > 0, b > 0) |
1. . O (0,0).
2. .
3. . 2 : A 1( a, 0) A 2(a, 0) .. .
4. A 1 A 2 , 2 a. B 1(0, b) B 2(0, b) , . B 1 B 2 , 2 b.
II .4 , , .
5. , F 1( C, 0) F 2(C, 0), , .
: M, | | F 1 M | | F 2 M | | = 2 a, .. , , , , 2 a > 0.
6. ε = C / a.
, ε > 1.
7. z 1: x = a / ε z 2: x = a / ε , .
, , ε < 1, .
. , .
8. , , : , F 1 . M, , F 2 M; .., . M, , T, MF 1 MF 2.
9. : ( , ).
|
|
. 7.2
. 7.2 .
. , , .
. , , . , , 2 a 2 b. () . .
IV | y 2 = 2 px (p > 0) |
1. , , .. .
2. .
3. . (0,0), .. .
4. p > 0 .
5. , p /2, .
6. , p /2, . , , , .. , .
: M, , | FM| = ρ (M,L), .. | FM | / ρM (L) = 1 , ε = 1. , , ε < 1, , ε > 1.
. , , .
7. : , , , , .. , .
. 7.3 .
|
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. 7.3
. , .
Ax 2 + By 2 + Cx + Dy + E = 0.
, .