Which of the following utility functions is an example of Cobb-Douglas preferences?
A) $U ( x , y ) = y \sqrt { x }$
B) $U ( x , y ) = \min \{ 2 x , y \}$
C) $U ( x , y ) = 3 x + 5 y$
D) $U ( x , y ) = 2 x ^ { 2 } + 4 y$

Question

Which of the following utility functions is an example of Cobb-Douglas preferences? 
A) $U ( x , y ) = y \sqrt { x }$
B) $U ( x , y ) = \min \{ 2 x , y \}$
C) $U ( x , y ) = 3 x + 5 y$
D) $U ( x , y ) = 2 x ^ { 2 } + 4 y$

Quizplus · Accepted Answer

Cobb-Douglas utility functions have the form $U(x,y) = x^ay^b$ where a and b are constants that determine the degree of substitutability between x and y. Choice A has the same form as a Cobb-Douglas function with a=1/2 and b=1, making it the only option that fits the criteria.

Which of the Following Utility Functions Is an Example of Cobb-Douglas