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

Multiple Choice

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

A) $a _ { n } = 2 \cdot ( 2 ) ^ { n - 1 }$
$\mathrm { r } = 2 ; 2,4,8,16 , \ldots$

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

C) $a _ { n } = 2 \left( \frac { 1 } { 2 } \right) ^ { n - 1 }$
$\mathrm { r } = \frac { 1 } { 2 } ; 2,1 , \frac { 1 } { 2 } , \frac { 1 } { 4 } , \ldots$

D) $\mathrm { a } _ { \mathrm { n } } = \frac { 1 } { 2 } ( 2 ) ^ { \mathrm { n } - 1 }$
$\mathrm { r } = \frac { 1 } { 2 } ; 2,4,8,16 , \ldots$