Answers For Conic Sections in Standard Form

Mr. Clausen                                       Algebra 2

 

Parabolas

 

#

Problem

Opening

Width

Vertex

Axis

Focus

Directrix

Points

1

y = 2(x-3)2 +4

Up

Narrow

(3,4)

x = 3

(3,  4 1/8)

y = 3 7/8

(4,6) (5,12) (6,22)

2

y = 1/2(x+1)2 - 2

Up

Wide

(-1,-2)

x = -1

(-1, -1 1/2)

y = -2.5

(0,-1.5) (1,0) (2, 2.5)

3

y = -4(x – 2) 2 +5

Down

Narrow

(2,5)

x = 2

(2, 4 15/16)

y = 5 1/16

(3,1) (4,-11)

4

y = -1/3(x – 3) 2 +1

Down

Wide

(3,1)

x = 3

(3, 1/4)

y =  1.75

(4, 2/3) (5, -1/3) (6,-2)

5

y =  -2(x + 1) 2 -1

Down

Narrow

(-1,-1)

x = -1

(-1, -1/8)

y = -7/8

(0, -3) (1, -9) (2, -19)

6

x = 2/3(y – 1)2 +1

Right

Wide

(1,1)

y = 1

(1 3/8, 1)

x = 5/8

(1 2/3, 2) (3 2/3, 3)

7

x = 4(y – 3)2 - 4

Right

Narrow

(-4,3)

y = 3

(3 7/8, 3)

x = -4 1/8

(0,4) (12,5)

8

x = -2(y + 1)2 +3

Left

Narrow

(3, -1)

y = -1

(2 7/8, -1)

x = 3 1/8

(1,0) (-5,1) (-15,2)

9

x = -1/2(y – 2)2 - 5

Left

Wide

(-5,2)

y = 2

(-5 1/2, 2)

x = -4 1/2

(-5 1/2, 3) (-7,4)

10

x = 3(y + 4)2 +3

Right

Narrow

(3, -4)

y = - 4

(3 1/12, -4)

x = 2 11/12

(15,-2) (-7, 4)

 

 

Circles

 

#

 Problem

Center

Radius

1

x2 + y2=36

(0,0)

6

2

x2 + (y-3)2 =16

(0,3)

4

3

(x-2)2 + y2=25

(2,0)

5

4

(x+1)2 + (y-5)2=49

(-1,5)

7

5

(x-3)2 + (y+2)2=81

(3,-2)

9

6

(x+5)2 + (y -1)2 =121

(-5,1)

11

7

(x-3/2)2 + (y + 9/2)2 =16

(3/2, -9/2)

4

8

(x + 1)2 + (y – 1)2 =12

(-1,1)

  3.4

9

(x -3/4)2 + (y + 1/6)2 = 8

(3/4, -1/6)

 2.8

10

(x + 10)2 + (y - 5) 2 = 7

(-10,5)

 2.6

 


Ellipses

 

#

Problem

Direction

Center

a

b

c

same direction as “a”

Vertices

Foci

1

x2/16 + y2/9=1

Horizontal

(0,0)

4 (left & right)

3 (up & down)

  2.6

(4,0) (-4,0)

(0,3) (0,-3)

(2.6,0) (-2.6,0)

2

x2/25 + (y-3)2  /4 =1

Horizontal

(0,3)

5 (left & right)

2 (up & down)

  4.6

(5,3) (-5,3)

(0,5) (0,1)

(4.6,3) (-4.6,3)

3

(x+1)2/49 + (y+2)2/25 =1

Horizontal

(-1,-2)

7 (left & right)

5 (up & down)

  4.9

(-8,-2) (6,-2)

(-1,3) (-1,-7)

(-5.9,-2) (3.9,-2)

4

(x-4)2/12 + (y+3)2/8 =1

Horizontal

(4,-3)

  3.5

(left & right)

* 2.8

(up & down)

2

(7.5,-3) (0.5,-3)

(4, 0.2) (4, -5.8)

(6,-3) (2,-3)

5

x2/4 + y2/25 =1

Vertical

(0,0)

5 (up & down)

2 (left & right)

  4.6

(2,0) (-2,0)

(0,5) (0,-5)

(0,4.6) (0,-4.6)

6

(x-3)2/4 + y2/16 =1

Vertical

(3,0)

4 (up & down)

2 (left & right)

 3.5

(5,0) (1,0)

(3,4) (3,-4)

(3, 3.5) (3, -3.5)

7

(x+4)2/25 + (y+5)2/36 =1

Vertical

(-4,-5)

6 (up & down)

5 (left & right)

   3.3

(-9,-5) (1,-5)

(-4,1) (-4,-11)

(-4, -8.3)

 (-4,-1.7)

8

(x-2)2/4 + (y+3)2/9 =1

Vertical

(2,-3)

3 (up & down)

2 (left & right)

 2.2

(5,-3) (-1,-3)

(2,0) (2,-6)

(2, -5.2) (2,-0.8)

 

Hyperbolas

 

#

Problem

Direction

Center

a

b

c

same direction as “a”

Vertices

Foci

1

x2/4 - y2/9=1

Horiz

(0,0)

2 (left & right)

3 (up & down)

 3.6

(2,0) (-2,0)

(-3.6, 0) (3.6, 0)

2

(x+1)2/16 - (y+2)2/9=1

Horiz

(-1,-2)

4 (left & right)

3 (up & down)

5

(-5,-2) (3,-2)

(-6, -2) (4, -2)

3

(x-3)2/16 - (y+4) 2/25=1

Horiz

(3,-4)

4 (left & right)

5 (up & down)

 6.4

(-1,-4) (7, -4)

(-3.4, -4) (9.4, -4)

4

(x-2)2/36 - (y+2)2/16=1

Horiz

(2,-2)

6 (left & right)

4 (up & down)

 7.2

(-4,-2) (8,-2)

(-5.2, -2) (9.2, -2)

5

y2/4 - x2/9 =1

Vert

(0,0)

2 (up & down)

3 (left & right)

 3.6

(0,2) (0,-2)

(0, 3.6) (0, -3.6)

6

(y-1)2/9 - (x-2)2/4 = 1

Vert

(2,1)

3 (up & down)

2 (left & right)

 3.6

(2, 4) (2,-2)

(2, 4.6) (2, -2.6)

7

(y+2)2/16 – (x+3)2/25=1

Vert

(-3,-2)

4 (up & down)

5 (left & right)

 6.4

(-3, 2) (-3,-6)

(-3, 4.4) (-3, -8.4)

8

(y-3)2/36 – (x-4)2/25=1

Vert

(4,3)

6 (up & down)

5 (left & right)

 7.8

(4,9) (4,-3)

(4, 10.8) (4, -4.8)