State the algebraic condition for the function \(\mathrm { f } ( x )\) to be an even function.
What geometrical property does the graph of an even function have?
State whether the following functions are odd, even or neither.
(A) \(\mathrm { f } ( x ) = x ^ { 2 } - 3\)
(B) \(\mathrm { g } ( x ) = \sin x + \cos x\)
(C) \(\mathrm { h } ( x ) = \frac { 1 } { x + x ^ { 3 } }\)