Ellipses

Question 1

What is the general equation for an ellipse?

Answer 1

(x²/a²) + (y²/b²) = 1

Where b² = a²(1 - e²); e = eccentricity

Question 2

What is the area of an ellipse?

Answer 2

πab

b² = a²(1 - e²)

So b = [a²(1 - e²)]½

Question 3

What are the coordinates of the foci of an ellipse?

Answer 3

(-ae), and (+ae)

Question 4

What are the coordinates of the directrix of an ellipse?

Answer 4

+a/e and -a/e