Answer: x2/a2 + y2/b2 = 1, a > b.
- A x2/a2 + y2/b2 = 1, a > b
- B x2/a2 - y2/b2 = 1
- C y2 = 4ax
- D x2 + y2 = a2
Correct answer: A. x2/a2 + y2/b2 = 1, a > b
Explanation: x2/a2 + y2/b2 = 1 with a > b > 0 is the standard ellipse equation with the major axis along the x-axis.
All four conics form a single family distinguished only by eccentricity: a circle is the most "closed" (e=0), an ellipse is an elongated closed curve, a parabola is the borderline open curve (e=1), and a hyperbola has two separate open branches (e>1).
Concept context
Study circles, parabolas, ellipses, and hyperbolas as curves formed by intersecting a plane with a double cone, with their standard equations and key properties.