Question

What are the foci of the following graph?

	A.	(2 - , 1) and (2 + , 1)
	B.	(2 - , 2) and (2 + , 2)
	C.	(2, 1) and (-2, 1)
	D.	(-3, 1) and (3, 1)

 

Answer 1

Observe the graph, the ellipse is horizontal.

Center of ellipse (h, k ) = (2, 2)

• Vertices of ellipse (h + a, k ), (h - a , k ) = (-1, 2) , (5, 2)

h + a  = - 1

Substitute the h  value in h + a = - 1

2 + a  = - 1

a  = - 3

• co - vertices are (h, k + b ) , (h, k - b ) = (2, 0), (2, 4)

Substitute k  = 2 in k + b  = 0

2 + b  = 0

b  = - 2

c  is the distance from center to each focus.

Foci (h  + c , k ) (h - c , k )

Option B is correct answer.