Which is the equation of an ellipse with directrices at y = ±4 and foci at (0, 2) and (0, −2)? x squared over 16 minus y squared over 4 equals 1 x squared over 4 plus y squared over 16 equals 1 x squared over 8 minus y squared over 4 equals 1 x squared over 4 plus y squared over 8 equals 1

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Answer:

x squared over 4 plus and squared over 8 equals 1, x^2/4 + y^2/8 = 1

Step-by-step explanation:

We have that the general ellipse equation is as follows:

x^2/a^2 + y^2/b^2 = 1

Furthermore, the foci is (0, c) and b> a we have to:

c ^ 2 = b ^ 2 - a ^ 2

However,

guideline x = + - b / e and foci (0, + - ab)

where is e is the eccentricity, therefore:

b / e = 4, then e = b / 4

and we also have b * e = 2, we replace:

b * (b / 4) = 2

b ^ 2 = 8

replacing:

2 ^ 2 = 8 - a ^ 2

a ^ 2 = 8 - 2 ^ 2

a ^ 2 = 8 - 4

a ^ 2 = 4

Therefore if we replace in the general equation it would be

x^2/4 + y^2/8 = 1

that is, x squared over 4 plus and squared over 8 equals 1

Answer:

x^2/4 + y^2/8 = 1

Step-by-step explanation: