The function \({\rm{f}}\left( {\rm{x}} \right) = \frac{{{{\rm{x}}^2}}}{{{{\rm{e}}^{\rm{x}}}}}\) is monotonically increasing if

The function \({\rm{f}}\left( {\rm{x}} \right) = \frac{{{{\rm{x}}^2}}}

1.	The function \({\rm{f}}\left( {\rm{x}} \right) = \frac{{{{\rm{x}}^2}}}{{{{\rm{e}}^{\rm{x}}}}}\) is monotonically increasing if
A.	x < 0 only
B.	x > 2 only
C.	0 < x < 2
D.	x ∈ (-∞, 0) ∪ (2, ∞)
Answer» D. x ∈ (-∞, 0) ∪ (2, ∞)