Match the function with its graph (labeled I- VI). Give reasons for your choices.

a) f(x, y) = 1 / 1 + x2 + y2

b) f(x, y) = 1 / 1 + x2y2

c) f(x, y) = ln(x2 + y2)

d) f(x, y) = cos √x2 + y2

e) f(x, y) = (x2 - y 2)2

f) f(x, y) = cos(xy)

Match the function with its graph (labeled I- VI). Give reasons for your choices.

a) f(x, y) = 1 / 1 + x2 + y2

b) f(x, y) = 1 / 1 + x2y2

c) f(x, y) = ln(x2 + y2)

d) f(x, y) = cos √x2 + y2

e) f(x, y) = (x2 - y 2)2

f) f(x, y) = cos(xy)