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Conic section: Definition and Example

Math Glossary: Geometry – Mathbot, the Math Made Easy robot coach

Definition: A conic section is a curve formed by slicing a double cone with a plane; the possible shapes are circles, ellipses, parabolas, and hyperbolas.

Grade 12 – Precalculus

What are the conic sections?

Slice a double cone at different angles and you get four families: the circle, ellipse, parabola, and hyperbola. Each has a standard equation, a center or vertex, and special points called foci.

How do you identify one?

  • x2 and y2 with equal positive coefficients: circle.
  • x2 and y2 with different positive coefficients: ellipse.
  • x2 and y2 with opposite signs: hyperbola.
  • Only one variable squared: parabola.

Worked example: x2 + y2 – 6x + 4y – 12 = 0. Complete the square: (x – 3)2 + (y + 2)2 = 12 + 9 + 4 = 25. It is a circle with center (3, -2) and radius 5.

What mistake is common?

Forgetting to add the same numbers to both sides when completing the square. Mathbot keeps the equation balanced step by step.

Example: x^2 + y^2 – 6x + 4y – 12 = 0 is a circle, center (3, -2), radius 5

Where to learn it

Related terms

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