Which of the Following Is a Homogeneous Function?

A) $f ( x , y ) = \cos ( x y ) f ( x , y ) = \cos ( x y )$

Multiple Choice

Which of the following is a homogeneous function?

A) $f ( x , y ) = \cos ( x y ) f ( x , y ) = \cos ( x y )$
B) $f ( x , y ) = 2 x ^ { 5 } - 3 x ^ { 4 } y - y ^ { 5 }$
C) $f ( x , y ) = \sin ( x y ) - x$
D) $f ( x , y ) = 2 x - x ^ { 2 } y ^ { 3 } + y ^ { 2 }$
E) $f ( x , y ) = x ^ { 2 } - x ^ { 2 } y ^ { 3 } + y ^ { 2 }$