ECAT · Mathematics · 5 questions
Name: ____________________ Date: ____________
What are the centre and radius of the circle x² + y² - 6x + 8y = 0?
What is the length of the major axis of the ellipse x² / 9 + y² / 4 = 1?
What are the asymptotes of the hyperbola x² - y² = 1?
What is the focus of the parabola x² = 12y?
What is the eccentricity of a parabola?
1. C, 2. D, 3. B, 4. C, 5. C
Completing the square gives (x - 3)² + (y + 4)² = 25, so the centre is (3, -4) and the radius is 5.
The larger denominator is 9, so a = 3 and the major axis has length 2a = 6.
For x² - y² = 1 the asymptotes come from x² - y² = 0, which gives y = x and y = -x.
Comparing with x² = 4ay gives 4a = 12, so a = 3 and the focus is (0, 3).
A parabola is defined by its distance to the focus equalling its distance to the directrix, so e = 1.