$\lim _ { x \rightarrow 0 } \frac { \left( e ^ { x } - 1 \right) \tan ^ { 2 } x } { x ^ { 3 } }$
(a) does not exist
(b) exists and equals 0
(c) exists and equals $\frac { 2 } { 3 }$
(d) exists and equals 1.
(d) Observe that $\frac { \left( e ^ { x } - 1 \right) \tan ^ { 2 } x } { x ^ { 3 } } = \frac { \left( e ^ { x } - 1 \right) } { x } \cdot \frac { \sin ^ { 2 } x } { x ^ { 2 } } \cdot \frac { 1 } { \cos ^ { 2 } x }$.
$\lim _ { x \rightarrow 0 } \frac { \left( e ^ { x } - 1 \right) \tan ^ { 2 } x } { x ^ { 3 } }$\\
(a) does not exist\\
(b) exists and equals 0\\
(c) exists and equals $\frac { 2 } { 3 }$\\
(d) exists and equals 1.