A Geometric Sequence Is Given $$\left\{ 4 \left( \frac { 1 } { 2 } \right) ^ { n - 1 } \right\}$$

Multiple Choice

A geometric sequence is given. Find the common ratio and write out the first four terms.
- $$\left\{ 4 \left( \frac { 1 } { 2 } \right) ^ { n - 1 } \right\}$$

A) $a _ { n } = 4 \cdot ( 2 ) ^ { n - 1 }$
$r = 2 ; 4,8,16,32 , \ldots$
B) $a _ { n } = \frac { 1 } { 2 } ( 4 ) ^ { n - 1 }$
$$\mathrm { r } = \frac { 1 } { 2 } ; 4,8,16,32 , \ldots$$
C) $\mathrm { a } _ { \mathrm { n } } = 4 \left( \frac { 1 } { 2 } \right) ^ { \mathrm { n } - 1 }$
$\mathrm { r } = \frac { 1 } { 2 } ; 4,2,1 , \frac { 1 } { 2 } , \ldots$
D) $\mathrm { a } _ { \mathrm { n } } = 4 \left( \frac { 1 } { 4 } \right) ^ { \mathrm { n } - 1 }$
$r = \frac { 1 } { 4 } ; 4,1 , \frac { 1 } { 4 } , \frac { 1 } { 16 } , \ldots$