$$f ( x ) = \frac { x } { x + \sin x } \quad \text { and } \quad g ( x ) = \frac { x ^ { 4 } + x ^ { 6 } } { e ^ { x } - 1 - x ^ { 2 } }$$
(a) Limit as $x \rightarrow 0$ of $f ( x )$ is $\frac { 1 } { 2 }$.\\
(b) Limit as $x \rightarrow \infty$ of $f ( x )$ does not exist.\\
(c) Limit as $x \rightarrow \infty$ of $g ( x )$ is finite.\\
(d) Limit as $x \rightarrow 0$ of $g ( x )$ is 720.