Math 208 (Lutz) - Quiz #2, 1/24/14
Name:
Directions: This quiz has 3 questions, for a total of 20 points. Solve each problem carefully. You must
show ALL of your work in order to earn full credit.
1. (6 points) Give an equation for the plane that passes through the points (1, 3, 6), (3, 3, 5), and (1, 4, 8).
2. (6 points) Find a unit vector in the direction of !v = 2!i − !j −
√
11!k.
3. (8 points) Let f (x, y) given by
f (x, y) =
x2 − y 2
.
x2 + y 2
Show that f does not have a limit as (x, y) → (0, 0).
Note: A complete solution to this problem must include a brief written explanation of how your
work establishes that f does not have a limit as (x, y) → (0, 0).