3. Draw the contour maps of

corresponding to c = 10, 20, 50, and 100.

Solution: The contour for z = c is

The various contours are

c

contour

10

x2 + 5y2 = 9

20

x2 + 5y2 = 4

50

x2 + 5y2 = 1

100

x2 + 5y2 = 0

The corresponding graphs are