Calculus Volume 3 · free preview

Quadric Surfaces

Quadric surfaces are the graphs of quadratic equations in three variables, the ellipsoid, hyperboloids of one and two sheets, the elliptic paraboloid, and the hyperbolic paraboloid classified by cross sections and signs.

1. The quadric family

The quadric family

2. Paraboloids and cones

Paraboloids and cones

3. Cross sections and standard form

Cross sections and standard form

4. Cylinders as degenerate quadrics

Cylinders as degenerate quadrics

5. Ellipsoid traces

Cross sections of the ellipsoid x^2/a^2 + y^2/b^2 + z^2/c^2 = 1 parallel to the xy plane are which curves?

6. One negative term

The surface x^2/a^2 + y^2/b^2 - z^2/c^2 = 1, with one negative term, is which quadric?

7. Saddle identification

The hyperbolic paraboloid z = x^2/a^2 - y^2/b^2 is commonly called what?

8. Completing the square purpose

Completing the square on a general quadratic brings a quadric's equation to what?

9. Cooling tower shape

The hyperboloid of one sheet is used for cooling towers because of which property?

10. Ellipsoid semi-axis count

The ellipsoid has three semi-axes a, b, and which third letter? Answer with one lowercase letter.

11. Cone degeneracy

The cone is the degenerate quadric separating the hyperboloids, its equation equating z squared to a sum. As a two-word name, what is it called? Answer like double cone.

12. Saddle minimax

The saddle curves upward along one axis and downward along the other, the landscape of which optimization concept? Answer with one word.

13. Sphere as special ellipsoid

The sphere x^2 + y^2 + z^2 = r^2 is the special case of the ellipsoid with what?

14. Negative term count two sheets

The hyperboloid of two sheets has how many negative squared terms? Answer with a number.

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