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7.3. | |
7.3. 1 | x 2 y 2 = a 2 45 . a = -45, : ¢¢ = 2/2. |
7.3. 2 | 5 x 2 + 9 y 2 30 x + 18 y + 9 = 0 . , : (5 x 2 30 x) + (9 y 2 + 18 y) +9 = 0, 5 (x 2 6 x) + 9(y 2 + 2 y) +9 = 0. : 5(x 2 6 x + 9 9) + 9(y 2 + 2 y + 1 1) + 9 = 0, 5(x 3)2 + 9(y + 1)2 = 45. x¢ = x 3, y¢ = y + 1, x 0 = 3, y 0 = -1, 1(3, -1) . : = 3, b = 1 (3, -1). |
7.3. 3 | (7) .4.4: : . x¢ 2 + 2 y¢ 2 = 2. |
7.3. 4 | , x 2 + y 2 + xy 2 x + 3 y = 0. 1( 0, 0), ¢ ¢ . : (x¢ + x 0)2 + (x¢ + x 0)(y¢ + y 0) + (y¢ + y 0)2 2(x¢ + x 0) + 3(y¢ + y 0) = 0 x¢2 + x¢y¢ + y¢2 + (2x0 + y0 - 2)x¢ + (x0 + 2y0 + 3)y¢ + x02 + x0y0 + y02 - 2x0 + 3y0 =0. 2 x 0 + y 0 2 = 0, x 0 + 2 y 0 + 3 = 0. : x 0 = 7/3 y 0 = -8/3. , O 1(7/3, -8/3), x ¢2 + x¢y¢ + y¢ 2 = 93/25. a, ¢¢. : (cos2a + sina×cosa + sin2a)× x ¢¢2 + (cos2a - sin2a)× x¢¢y¢¢ + + (sin2a - sina×cosa + cos2a)× y¢¢ 2 = 93/25. cos2a - sin2a = 0, tg2a = 1. , a1,2 = 45. a = 45, cos45 = sin45 = , , 1(7/3, -8/3) 45 . x 2 + y 2 + xy 2 x + 3 y = 0 |
7.3. 5 | 4 x 2 4 xy + y 2 2 x 14 y + 7 = 0. : , , . , a, : : 4 x 2 4 xy + y 2 2 x 14 y + 7 = (4cos2a - 4cosa×sina + sin2a)× x¢2 + + 2×(-4sina×cosa - 2cos2a + 2sin2a + sina×cosa)× x¢y¢ + + (4sin2a + 4sina×cosa + cos2a)× y¢ 2 + + 2×(-cosa - 7sina)× x¢ + 2×(sina - 7cosa)× y¢ + 7 = 0. (*) a , ¢¢ . -4sina×cosa - 2cos2a + 2sin2a + sina×cosa = 0. 2sin2a - 3sina×cosa - 2cos2a = 0, 2tg2a - 3tga - 2 = 0. tga = 2, tga = -1/2. , . tga, cosa sina: , (*), ¢,¢: (**) (**) ¢, ¢. (**) : , : ¢¢,¢¢, x¢ = x¢¢ + y¢ = y¢¢ + ¢ ¢. ¢¢¢¢ ¢¢¢¢. ¢¢ . ¢ ¢ |
7.3. 6 | 4 x 2 - 4 xy + y 2 + 4 x - 2 y - 3 =0? : 2 0 0 + 1 = 0, , , 2 + 1= 0. , : 4 2 4 + 2 + 4 2 3 =(2 + 3)(2 1). , : 2 + 3 = 0 2 1 = 0. |
7.3. 7 | 1. 5 2 + 6 + 5 2 4 + 4 + 12 = 0 ¢ 2 + 4 ¢ 2 + 4 = 0, . , ¢, ¢ , c 1. . 2. 5 2 + 6 + 5 2 4 + 4 + 4 = 0 ¢ 2 + 4 ¢ 2 = 0, , , : ¢ = 0, ¢ = 0. . |
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7.3. 8 | , F (2, -1) D: x y 1 = 0. ¢ 1 ¢ ¢2 = 2 ¢. = 1 , ¢ 1 ¢ . , 1, D, . , 1¢ = - + b, -1 = -2 + b. b = 1 1 ¢: = - + 1. K 1 ¢ : 1( 0, 0): (-45). = KF = , , y¢ 2 = ×x ¢ (. (5) .4.3): : 2 + 2 + 2 6 + 2 + 9 = 0. |
7.3. 9 | , = F (2, -3) 3 + 3 = 0. D 1: = 3 + 3 , ¢ y = (-1/3) x + b, F (2, -3), , b = -7/3 ¢ 1( 0, 0). D 1 ¢¢ , ¢¢ F F (2, -3) D1: 3 + 3 = 0. b 2 = 18. , 1 F D : sina = cosa = (-a): sin(-a) = cos(-a) = (. (5) .4.3) : 4(3 +6)2 ( + 3 + 7)2 = 180 7 2 2 6 18 + 26 + 17 = 0. |