Find a General Term an for the Geometric Sequence $$\mathrm { a } _ { 1 } = \frac { 1 } { 2 } , \mathrm { r } = 2$$

Multiple Choice

Find a general term an for the geometric sequence.
- $$\mathrm { a } _ { 1 } = \frac { 1 } { 2 } , \mathrm { r } = 2$$

A) $a _ { n } = \frac { 1 } { 2 } \cdot 2 ^ { n - 1 }$
B) $a _ { n } = \left( \frac { 1 } { 2 } \right) n - 1 + \frac { 1 } { 2 }$
C) $\mathrm { a } _ { \mathrm { n } } = \frac { 1 } { 2 } + \frac { 1 } { 2 } ( \mathrm { n } - 1 )$
D) $a _ { n } = \frac { 1 } { 2 } + 2 ( n - 1 )$