Determine Whether $f ( x ) = 5 x ^ { 2 } - \frac { x ^ { 4 } } { 5 }$

Essay

Determine whether $f ( x ) = 5 x ^ { 2 } - \frac { x ^ { 4 } } { 5 }$ is even or odd. If $f$ is even or odd, use symmetry to sketch its graph.