2 The first two non-zero terms of the Maclaurin series expansion of \(\mathrm { f } ( x )\) are \(x\) and \(- \frac { 1 } { 2 } x ^ { 3 }\)
Which one of the following could be \(\mathrm { f } ( x )\) ?
Circle your answer.
\(x \mathrm { e } ^ { \frac { 1 } { 2 } x ^ { 2 } }\)
\(\frac { 1 } { 2 } \sin 2 x\)
\(x \cos x\)
\(\left( 1 + x ^ { 3 } \right) ^ { - \frac { 1 } { 2 } }\)