Solução_Calculo_Stewart_6e

F.
TX.10
SECTION 10.5 CONIC SECTIONS ¤ 437
10.5 Conic Sections
1. x =2y 2 ⇒ y 2 = 1 x. 4p = 1 ,sop = 1 .Thevertex
2 2 8
3. 4x 2 = −y ⇒ x 2 = − 1 y. 4p = − 1 ,sop = − 1 .
is (0, 0),thefocusis 4 4 16
1
, 0 , and the directrix is x = − 1 . The vertex is (0, 0),thefocusis
0, − 1 8 8 16 ,andthe
directrix is y = 1
16 .
5. (x +2) 2 =8(y − 3). 4p =8,sop =2.Thevertexis
(−2, 3),thefocusis(−2, 5), and the directrix is y =1.
7. y 2 +2y +12x +25=0 ⇒
y 2 +2y +1=−12x − 24 ⇒
(y +1) 2 = −12(x +2). 4p = −12,sop = −3.
The vertex is (−2, −1),thefocusis(−5, −1),andthe
directrix is x =1.
9. The equation has the form y 2 =4px,wherep